八日市场市 是千叶县东北部的一个已不存在的市。2006年1月23日，与隣接的匝瑳郡野荣町合并为匝瑳市。

Yōkaichiba(八日市場市,Yōkaichiba-shi) was a city located in northeastern Chiba Prefecture, Japan.

Fukuoka Town was established on April 1, 1889 within Sōsa District, Chiba. It changed its name to Yōkaichiba on December 8, 1915. On March 31, 1954, the town expanded greatly through the annexation of the neighboring villages of Heiwa, Chinkai, Sōsa, Toyosaka, Suga, Kyōkō, Yoshida, Iidaka, and Toyowa, all within Sōsa District. Yōkaichiba was elevated to city status on July 1, 1954.