Surname ヒロマサ (ヒロマサ 
, Hiromasa 
) , in all the world, is a common family name. The surname ヒロマサ is characteristic of Japan, where it is quite a rare surname, Taiwan, where it is a rare surname, and the United States, where it is a very rare surname. Measured by absolute frequency, it is the most numerous in Eastern Asia, particularly Japan, Taiwan, and China. Very seldom, ヒロマサ is the forename as well as the last name.