A dust collecting device 140 is provided which is attached to an electric hammer 101 having a side handle 110 which is removably attached to a body 103. The dust collecting device 140 has a dust collecting hood 141 and a hose holder 145. The side handle 110 has a mounting ring 111 which is mounted on the body 103, a grip 121 and a grip securing part 131. The grip 121 is secured by moving relative to the grip securing part 131 in a direction crossing an axial direction of the hammer bit 200. By this relative movement for securing the grip 121, the hose holder 145 is held between the grip 121 and the grip securing part 131.