diff --git a/src/main/java/com/acquirex/cardacquisition/service/CardAcquisitionService.java b/src/main/java/com/acquirex/cardacquisition/service/CardAcquisitionService.java
new file mode 100644
index 0000000..f538519
--- /dev/null
+++ b/src/main/java/com/acquirex/cardacquisition/service/CardAcquisitionService.java
@@ -0,0 +1,106 @@
+package com.acquirex.cardacquisition.service;
+
+import com.acquirex.cardacquisition.entity.CardAcquisition;
+import com.acquirex.cardacquisition.repository.CardAcquisitionRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.UUID;
+import java.util.stream.Collectors;
+
+@Service
+public class CardAcquisitionService {
+
+    private static final BigDecimal MAX_SINGLE_TRANSACTION = new BigDecimal("10000000");
+    private static final BigDecimal DAILY_LIMIT = new BigDecimal("50000000");
+
+    private final CardAcquisitionRepository repository;
+
+    public CardAcquisitionService(CardAcquisitionRepository repository) {
+        this.repository = repository;
+    }
+
+    @Transactional
+    public AcquisitionResponse requestAcquisition(AcquisitionRequest request) {
+        validateRequest(request);
+
+        CardAcquisition acquisition = new CardAcquisition(
+                request.getMerchantId(), request.getCardNumber(), request.getAmount(), request.getCurrency());
+
+        CardAcquisition saved = repository.save(acquisition);
+        String approvalCode = generateApprovalCode();
+        saved.approve(approvalCode);
+
+        AcquisitionResponse response = AcquisitionResponse.fromEntity(repository.save(saved));
+        response.setMessage("매입 승인이 완료되었습니다");
+        return response;
+    }
+
+    @Transactional(readOnly = true)
+    public AcquisitionResponse getAcquisition(Long id) {
+        CardAcquisition acquisition = repository.findById(id)
+                .orElseThrow(() -> new AcquisitionNotFoundException("매입 정보를 찾을 수 없습니다: " + id));
+        AcquisitionResponse response = AcquisitionResponse.fromEntity(acquisition);
+        response.setMessage("매입 정보를 조회했습니다");
+        return response;
+    }
+
+    @Transactional(readOnly = true)
+    public List<AcquisitionResponse> getAcquisitionsByMerchant(String merchantId) {
+        return repository.findByMerchantId(merchantId).stream()
+                .map(AcquisitionResponse::fromEntity).collect(Collectors.toList());
+    }
+
+    @Transactional(readOnly = true)
+    public List<AcquisitionResponse> getPendingAcquisitions() {
+        return repository.findByStatus(CardAcquisition.AcquisitionStatus.PENDING).stream()
+                .map(AcquisitionResponse::fromEntity).collect(Collectors.toList());
+    }
+
+    @Transactional
+    public AcquisitionResponse cancelAcquisition(Long id) {
+        CardAcquisition acquisition = repository.findById(id)
+                .orElseThrow(() -> new AcquisitionNotFoundException("매입 정보를 찾을 수 없습니다: " + id));
+
+        if (acquisition.getStatus() == CardAcquisition.AcquisitionStatus.CANCELLED) {
+            throw new IllegalStateException("이미 취소된 매입입니다");
+        }
+
+        acquisition.setStatus(CardAcquisition.AcquisitionStatus.CANCELLED);
+        acquisition.setApprovalTime(LocalDateTime.now());
+
+        AcquisitionResponse response = AcquisitionResponse.fromEntity(repository.save(acquisition));
+        response.setMessage("매입이 취소되었습니다");
+        return response;
+    }
+
+    private void validateRequest(AcquisitionRequest request) {
+        if (request.getAmount().compareTo(MAX_SINGLE_TRANSACTION) > 0) {
+            throw new InvalidAcquisitionException("단일 거래 한도를 초과했습니다");
+        }
+
+        LocalDateTime startOfDay = LocalDateTime.now().toLocalDate().atStartOfDay();
+        BigDecimal todayTotal = repository.findByRequestTimeBetween(startOfDay, startOfDay.plusDays(1)).stream()
+                .filter(a -> a.getMerchantId().equals(request.getMerchantId()))
+                .map(CardAcquisition::getAmount).reduce(BigDecimal.ZERO, BigDecimal::add);
+
+        if (todayTotal.add(request.getAmount()).compareTo(DAILY_LIMIT) > 0) {
+            throw new InvalidAcquisitionException("일일 한도를 초과했습니다");
+        }
+    }
+
+    private String generateApprovalCode() {
+        return "APR" + UUID.randomUUID().toString().substring(0, 12).toUpperCase();
+    }
+
+    public static class AcquisitionNotFoundException extends RuntimeException {
+        public AcquisitionNotFoundException(String message) { super(message); }
+    }
+
+    public static class InvalidAcquisitionException extends RuntimeException {
+        public InvalidAcquisitionException(String message) { super(message); }
+    }
+}
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