Substantially cylindrical head tube body, center tube body and tip tube body threadedly engage each other to thereby construct a tool main body of a tool for wristwatch. The through hole of the center tube body is provided with a partition part having a small-diameter hole and slant face. A hammering member and compression spring are slidably accommodated in the through hole. A trigger shaft includes a small-diameter part which can be inserted in a center hole of the hammering member, and a large-diameter part continuing therefrom through the slant face, which can pass through the small-diameter hole. A deformed coil spring has the large-diameter part of the trigger shaft fitted therein in wound form, and energizes the trigger shaft toward sliding shaft while slanting the trigger shaft so as to cause the small-diameter part to shift toward the inside wall of the tool main body. The sliding shaft at its rear end includes large-diameter head part and at its front end includes an engagement part to which a wristwatch tool component can be replaceably fixed. The engagement part interlocks a small-diameter hole of the tip tube body with a play, and the front end of the engagement part protrudes from the tip tube body.