Masahiro Koishikawa (小石川 正弘 Koishikawa Masahiro, born 1952) is a Japanese astronomer He has studied both major and minor planets, and has discovered multiple asteroids.
Koishikawa has been a staff member of the Sendai Astronomical Observatory since 1972. His research is based out of the Sendai's Ayashi station.
Asteroid 6097 was discovered on October 29, 1991 by Kin Endate and Kazuro Watanabe at Kitami. The Main-belt asteroid was given the name 6097 Koishikawa in honor of Masahiro Koishikawa.
This is a partial list of discoveries made by Masahiro Koishikawa.