A valve opening-closing timing control device includes a housing member rotating together with one of a cam shaft and a crank shaft of a combustion engine, a rotor member rotatably attached to said housing member; and rotating together with the other of said crank shaft and said cam shaft, a hydraulic pressure chamber formed between said housing member and said rotor member, the hydraulic pressure chamber being divided into an advance angle hydraulic chamber and a retard angle hydraulic chamber by a vane integrally provided with said rotor member, a lock mechanism including a lock member movably provided at the housing member and a receiving portion formed at said rotor member for receiving the lock member, whereby the lock mechanism restricts a relative rotation between the rotor member and the housing member by advancing the lock member into the receiving portion and allows the relative rotation between the rotor member and the housing member by retracting the lock member from the receiving portion, a hydraulic pressure circuit for supplying hydraulic fluid to said advance angle hydraulic chamber, said retard angle hydraulic chamber, and said lock mechanism, and a projecting portion formed at a bottom of said receiving portion and including a top end face smaller than a sectional area of said lock member.