diff --git a/src/OptionParser.cc b/src/OptionParser.cc
index d2250374..157d74ec 100644
--- a/src/OptionParser.cc
+++ b/src/OptionParser.cc
@@ -347,4 +347,9 @@ const SharedHandle<OptionParser>& OptionParser::getInstance()
   return optionParser_;
 }
 
+void OptionParser::deleteInstance()
+{
+  optionParser_.reset();
+}
+
 } // namespace aria2
diff --git a/src/OptionParser.h b/src/OptionParser.h
index 617712db..2cd9f8e7 100644
--- a/src/OptionParser.h
+++ b/src/OptionParser.h
@@ -94,6 +94,9 @@ public:
   const OptionHandler* findByShortName(char shortName) const;
 
   static const SharedHandle<OptionParser>& getInstance();
+  // Deletes statically allocated instace. Call this at the end of the
+  // program.
+  static void deleteInstance();
 };
 
 } // namespace aria2
diff --git a/src/Platform.cc b/src/Platform.cc
index a2749a4e..298294ae 100644
--- a/src/Platform.cc
+++ b/src/Platform.cc
@@ -73,6 +73,8 @@
 #include "message.h"
 #include "fmt.h"
 #include "console.h"
+#include "OptionParser.h"
+#include "prefs.h"
 #ifdef HAVE_LIBGMP
 # include "a2gmp.h"
 #endif // HAVE_LIBGMP
@@ -172,7 +174,11 @@ bool Platform::tearDown()
 #ifdef HAVE_WINSOCK2_H
   WSACleanup();
 #endif // HAVE_WINSOCK2_H
-
+  // Deletes statically allocated resources. This is done to
+  // distinguish memory leak from them. This is handly to use
+  // valgrind.
+  OptionParser::deleteInstance();
+  option::deletePrefResource();
   return true;
 }
 
diff --git a/src/prefs.cc b/src/prefs.cc
index 6675de2e..62089096 100644
--- a/src/prefs.cc
+++ b/src/prefs.cc
@@ -51,6 +51,13 @@ public:
     // We add special null pref whose ID is 0.
     makePref("");
   }
+  ~PrefFactory()
+  {
+    for(size_t i = 0; i < count_; ++i) {
+      delete i2p_[i];
+    }
+  }
+
   size_t nextId()
   {
     return count_++;
@@ -117,6 +124,11 @@ const Pref* k2p(const std::string& key)
   return getPrefFactory()->k2p(key);
 }
 
+void deletePrefResource()
+{
+  delete getPrefFactory();
+}
+
 } // namespace option
 
 /**
diff --git a/src/prefs.h b/src/prefs.h
index 01ed3397..ec15169c 100644
--- a/src/prefs.h
+++ b/src/prefs.h
@@ -60,6 +60,10 @@ const Pref* i2p(size_t id);
 // special null Pref whose ID is 0.
 const Pref* k2p(const std::string& k);
 
+// Deletes resources allocated for preferences. Call this function at
+// the end of the program only once.
+void deletePrefResource();
+
 } // namespace option
 
 /**