Relief valve

The invention provides a relief valve capable of inhibiting nipping of foreign matters and allowing stable setting of relief pressure. A spool valve body (18) has an axial one side provided with a concave pressure receiving part (18A) for receiving pressures in said supply passage (13A), and a radial hole (18B) that radially communicates an inside and an outside of the pressure receiving part (18A) and penetrates through a front end cylinder part (18A1) of the pressure receiving part (18A) along the radial direction. An annular gap (22) is formed between an inner peripheral surface of an spool sliding bore (14D) adjacent to a displacement regulating part (14B) and an outer periphery of the front end cylinder part. At the opening of the spool valve body, a first oil passage (24) in which hydraulic oil flows to a tank port from a supply passage (13A) through the pressure receiving part and the radial hole along the direction of an arrow A and a second oil passage (25) in which the hydraulic oil flows to the tank port through an axial gap (23) and an annular gap (22) between the displacement regulating part and the front end cylinder part (18A1) along the direction of an arrow B, are formed.