An impact tool which performs a predetermined operation at least by linearly driving a tool bit detachably coupled to a front end region of a tool body (102, 103) in its axial direction comprising: a dust collecting device that sucks and collects dust generated during an operation by the tool bit, a body side mounting region that is formed in the tool body (102, 103), the body side mounting region attaching the dust collecting device to the tool body (102, 103) and a dust collecting device side mounting region that is formed in the dust collecting device, wherein: one of the body side mounting region and the dust collecting device side mounting region has a plurality of projections which extend in an axis direction of the tool bit and are arranged around the axis, and the other has a plurality of grooves which extend in the axis direction of the tool bit and are engaged with the projections, and a plurality of ridges provided between the grooves around an axis of the tool bit, the impact tool further comprising: a clamping member that clamps the body side mounting region and the dust collecting device side mounting region by fitting thereon from the outside, characterized in that: when the dust collecting device is attached to the tool body (102, 103) by engagement of the projections with the grooves, outer surfaces of the projections and top surfaces of the ridges are flush with each other in the circumferential direction, and the clamping member uniformly clamps the regions flush with each other, whereby the dust collecting device is fixedly attached to the tool body (102, 103). a dust collecting device that sucks and collects dust generated during an operation by the tool bit, a body side mounting region that is formed in the tool body (102, 103), the body side mounting region attaching the dust collecting device to the tool body (102, 103) and a dust collecting device side mounting region that is formed in the dust collecting device, wherein: one of the body side mounting region and the dust collecting device side mounting region has a plurality of projections which extend in an axis direction of the tool bit and are arranged around the axis, and the other has a plurality of grooves which extend in the axis direction of the tool bit and are engaged with the projections, and a plurality of ridges provided between the grooves around an axis of the tool bit, the impact tool further comprising: one of the body side mounting region and the dust collecting device side mounting region has a plurality of projections which extend in an axis direction of the tool bit and are arranged around the axis, and the other has a plurality of grooves which extend in the axis direction of the tool bit and are engaged with the projections, and a plurality of ridges provided between the grooves around an axis of the tool bit, the impact tool further comprising: a clamping member that clamps the body side mounting region and the dust collecting device side mounting region by fitting thereon from the outside, characterized in that: when the dust collecting device is attached to the tool body (102, 103) by engagement of the projections with the grooves, outer surfaces of the projections and top surfaces of the ridges are flush with each other in the circumferential direction, and the clamping member uniformly clamps the regions flush with each other, whereby the dust collecting device is fixedly attached to the tool body (102, 103). when the dust collecting device is attached to the tool body (102, 103) by engagement of the projections with the grooves, outer surfaces of the projections and top surfaces of the ridges are flush with each other in the circumferential direction, and the clamping member uniformly clamps the regions flush with each other, whereby the dust collecting device is fixedly attached to the tool body (102, 103).