A handheld electric power tool that is adapted to be driven in oscillation, the handheld electric power tool having a housing and a drive arranged in the housing for driving a toolholder, which is arranged on a tool shaft coupled to the drive and on which a tool is detachably installed. The tool shaft is accommodated in an output unit, which includes a gearhead accommodated in a gearhead housing, and a collar, which is designed so as to make possible a tool-free seating of an attachment in an installation direction oriented parallel to a longitudinal axis of the gearhead, is formed on the output unit.