diff --git a/src/BinaryDict.cpp b/src/BinaryDict.cpp
index fcfa0109..2e3fbc33 100644
--- a/src/BinaryDict.cpp
+++ b/src/BinaryDict.cpp
@@ -117,8 +117,8 @@ BinaryDictPtr BinaryDict::NewFromFile(FILE* fp) {
       throw InvalidFormat("Invalid OpenCC binary dictionary (numValues)");
     }
     // Key offset
-    size_t keyOffset;
-    unitsRead = fread(&keyOffset, sizeof(size_t), 1, fp);
+    long keyOffset;
+    unitsRead = fread(&keyOffset, sizeof(long), 1, fp);
     if (unitsRead != 1 || keyOffset >= offsetBound) {
       throw InvalidFormat("Invalid OpenCC binary dictionary (keyOffset)");
     }
@@ -126,8 +126,8 @@ BinaryDictPtr BinaryDict::NewFromFile(FILE* fp) {
     // Value offset
     std::vector<std::string> values;
     for (size_t j = 0; j < numValues; j++) {
-      size_t valueOffset;
-      unitsRead = fread(&valueOffset, sizeof(size_t), 1, fp);
+      long valueOffset;
+      unitsRead = fread(&valueOffset, sizeof(long), 1, fp);
       if (unitsRead != 1 || valueOffset >= offsetBound) {
         throw InvalidFormat("Invalid OpenCC binary dictionary (valueOffset)");
       }
diff --git a/src/PhraseExtract.cpp b/src/PhraseExtract.cpp
index 69c21bba..34c07a76 100644
--- a/src/PhraseExtract.cpp
+++ b/src/PhraseExtract.cpp
@@ -99,9 +99,9 @@ class PhraseExtract::DictType {
   }
 
   void BuildTrie() {
-    std::unordered_map<std::string, int> key_item_id_map;
+    std::unordered_map<std::string, size_t> key_item_id_map;
     marisa::Keyset keyset;
-    for (int i = 0; i < items.size(); i++) {
+    for (size_t i = 0; i < items.size(); i++) {
       const auto& key = items[i].first;
       key_item_id_map[key.ToString()] = i;
       keyset.push_back(key.CString(), key.ByteLength());
@@ -117,7 +117,7 @@ class PhraseExtract::DictType {
       if (it == key_item_id_map.end()) {
         throw ShouldNotBeHere();
       }
-      int item_id = it->second;
+      size_t item_id = it->second;
       marisa_id_item_map[marisa_id] = item_id;
     }
   }
@@ -127,7 +127,7 @@ class PhraseExtract::DictType {
       dict;
   std::vector<ItemType> items;
   marisa::Trie marisa_trie;
-  std::vector<int> marisa_id_item_map;
+  std::vector<size_t> marisa_id_item_map;
 };
 
 using namespace internal;