Since the first Japanese public museum was opened in 1926, the public museums have been playing the role as main cultural facilities in regional community. The purpose of this study is to describe the development process of Japanese public museums by analyzing their spatial configurations. This study treats 109 Japanese public museums. Analyses revealed that the scale of the public museums consistently became larger after the 2nd World War, and the number of newly-established public museums has increased until 1980s. Until 1960s, exhibition spaces were core of public museums. Since the 1980s, there are two types public museums. One type is variety arrangements of functional floor areas. Another type has distributed organizations of exhibition spaces.