Japanese Prime Minister has indicated that he doesn't have any plans to visit Pearl Harbor in reciprocation for Obama's visit to Hiroshima.
What Japanese government members have visited Pearl Harbor?
The Daily Mail in a 2009 article says that Lower house speaker Yohei Kono was the highest-ranking government member to do so, and reports that the Emperor planned to visit it, and the 1994 article Emperor Visits Site Near Pearl Harbor mentions that the Emperor visited a place near it.
I couldn't find any relevant info in Attack on Pearl Harbor, Naval Station Pearl Harbor or USS Arizona Memorial.