PURPOSE: To achieve a large travel amount of a slider by changing over gears arranged on a drive shaft of a hand tool with a transmission selectively to connect them with the drive shaft and providing the slider operable by a knob rotatable for sliding a change-over connection member.

CONSTITUTION: In a hammer drill with a transmission, latching openings 38a, 38b of which sides are opened to latch them on a knob 36 are provided in a slider 35 arranged movably in both directions, and interlocking projecting parts 37a, 37b arranged equal distance apart in the radial direction from a rotary axial line of the knob 36 are provided on the knob 36, respectively. A distance T between the latching openings 38a and 38b corresponds to a chord of a circular arc 1 between the interlocking projecting parts 37a and 37b, and the latching openings 38a, 38b are arranged at positions coinciding with a travel path of the interlocking projecting parts 37a, 37b. Consequently, the interlocking projecting parts 37a, 37b are continuously engaged with the latching openings 38a, 38b while the knob 36 rotates due to the latching openings 38a, 38b opened in opposition to the knob 36.