| Japan Proletarian Party 日本無産党 | |
| Native Name: | Nihon Musantō |
| Colorcode: | red |
| Founder: | Suzuki Mosaburō Katō Kanjū |
| Founded: | March 1937 |
| Banned: | 23 December 1937 |
| Wing1 Title: | Labour wing |
| Wing2 Title: | Women's wing |
| Wing3 Title: | Peasants' wing |
| Ideology: | Anti-Shakai Taishūtō Revolutionary socialism Socialism Agrarian socialism |
| Position: | Left-wing to Far-left |
| Country: | Japan |
was a short-lived leftist political party in early Shōwa period Japan.
The Nihon Musantō was founded by Suzuki Mosaburō and (1892–1978) in March 1937, as a political wing of the labor union movement.[1] Katō, its chairman, won a seat in the 1937 general election, but the party failed to create much popular support against the rising forces of militarism and against the rising inflation in the Japanese economy.
In December 1937, its members were arrested in the Popular Front Incident, and the party was disbanded.