"Kōfukuron" (幸福論, lit.The theory of happiness) is the debut single by Japanese singer Ringo Sheena and it was released on May 27, 1998 by Toshiba EMI, East World.

[1] "Kōfukuron" and "Suberidai" were produced by Hiroshi Kitashiro, who is an audio engineer and synthesizer programmer, and "Toki ga Bōsō Suru" was produced by Uni Inoue, who is an audio engineer and multi-instrumentalist.

Sheena wanted to release not "Kōfukuron" but B-side song "Suberidai" as a title tune.

Since Sheena was not pleased with the arrangement of "Kōfukuron," the single version was not included in the album.

The song was covered as a part of a medley by Rie Tomosaka on the television show The Yoru mo Hippare on September 9, 2000.