Master cylinder

In a master cylinder, a supply passage for supplying operating liquid from a reservoir to a pressure chamber is provided in a cylinder body coupled with the reservoir. A bypass passage for bypassing the supply passage and connecting the reservoir and the pressure chamber is further provided, and a check valve adapted to open when a pressure in the pressure chamber is lower than that in the reservoir is disposed in the bypass passage. A valve case containing a valve body of the check valve includes a valve seat and a cylindrical wall for slidably guiding the valve body which are integrally formed as a single member.