A main lock member is fitted in a main lock bore at a main lock phase for closing an intake valve at a timing later than a timing when a piston reaches a bottom dead center, whereby a rotation phase is locked. In a subordinate lock mechanism, the rotation phase is locked at a subordinate lock phase advancing further than the main lock phase. In a lock control mechanism, a temperature sensing body is changed to an expanded state, whereby a moving member is latched at a first position in which the main lock member is allowed to be fitted in the main lock bore, whereas at a main lock phase in a cold stop state after a timing when the temperature of the stopped internal combustion engine becomes less than a preset temperature, the temperature sensing body is changed to a contracted state.