Substantially cylindrical head tube body 1, center tube body 2 and tip tube body 4 threadedly engaged each other to thereby construct tool main body 5 of tool for wristwatch 20. Through hole 2c of the center tube body 2 is provided with partition part 2e having small-diameter hole 2d and slant face 2f. Hammering member 7 and compression spring 6 are slidably accommodated in the through hole 2c. Trigger shaft 8 includes small-diameter part 8a, which can be inserted in center hole 7a of the hammering member 7, and large-diameter part 8c continuing therefrom through slant face 8b, which can pass through the small-diameter hole 2d. Deformed coil spring 9 has the large-diameter part 8c of the trigger shaft 8 fitted therein in wound form, and energizes the trigger shaft 8 toward sliding shaft 11 while slanting the trigger shaft 8 so as to cause the small-diameter part 8a to shift toward the inside wall of the tool main body 5. The sliding shaft 11 at its rear end includes large-diameter head part 11a and at its front end includes engagement part 11b to which a wristwatch tool component can be replaceably fixed. The engagement part 11b interlocks small-diameter hole 4c of the tip tube body 4 with a play, and the front end of the engagement part 11b protrudes from the tip tube body 4.