A regulator for clutch actuator includes a housing having a cylindrical damping space inside, a first fluid path interconnecting the damping space and a master cylinder, and a second fluid path interconnecting the damping space and a an operating cylinder. The regulator further includes a flexible valve member contained in the damping space for reducing vibrations. The flexible valve member comprises a first inflow guiding portion configured to receive and guide fluid from the first fluid path. The first inflow guiding portion has a plurality of through holes such that elastic deformation of the first inflow guiding portion reduces vibration when fluid flow into the cylindrical damping space from the master cylinder.