A dust collector includes a body configured to be removably attached to a lower side of a tool body of a drilling tool, a dust storing part to be disposed on a lower side of the body, a sliding part having a suction port and held by the body so as to be slidable in a front-rear direction, a dust transfer passage extending within the sliding part and connecting the suction port and an inlet of the dust storing part, and a tool connection passage disposed within an internal space of the body and configured to connect an outlet of the dust storing part and an inlet of the tool body of the drilling tool. The dust storing part includes the inlet, a filter, a dust storing space and the outlet. The filter is disposed forward of the inlet of the dust storing part.