Abstract: In a flow rate control valve, a valve seat includes an annular base part and an annular seal part provided on the inner periphery thereof. A body includes a contact surface with which an end of the base part in the axial direction contacts and a press-fit surface against which the outer peripheral surface of the base part is press-fitted. The seal part includes: a seat surface at an end on an opposite side to the contact surface in the axial direction to contact a valve element to seal between the valve seat and the valve element in a valve closed state; and a valve-seat-to-body sealing portion protruding toward the contact surface more than the base part at an end on the side of the contact surface in the axial direction and contacting the contact surface to seal between the valve seat and the body.