A friction member is clamped between a driven shaft of an internal combustion engine and a vane rotor and includes an oil passage hole. The oil passage hole communicates between a first oil passage of the driven shaft a second oil passage of the vane rotor. Each of positioning arrangements includes a primary engaging portion of the vane rotor and a secondary engaging portion of the friction member. The positioning arrangements are configured to limit relative rotation between the vane rotor and the friction member in a communicating state where the first oil passage and the second oil passage are communicated with each other through the oil passage hole.