A dust collector for an electric power tool includes a main body case, a dust box, a sliding portion, and a dust collecting route. The main body case includes an exhaust port, the main body case being configured to be installed on an electric power tool. The dust box internally includes a filter. The sliding portion is disposed on the main body case. The sliding portion has a front end on which a nozzle with a suction opening is disposed. The sliding portion is slidable in a front-rear direction. The dust collecting route is from the suction opening to the exhaust port passing through the filter. The main body case includes a guiding portion through which the sliding portion passes, and the guiding portion allows the sliding portion to project rearward when the sliding portion slides.