An electric power tool and a power supply module for interchangeable attachment to an electric power tool are disclosed. The electric power tool has a tool housing (12) with a guide sleeve (15) for interchangeably receiving the power supply module (11), which has an introduction opening (152) and an electrical interface. To achieve high resistance to vibration of the contacting at the module/tool interface, at least one form-locking element (21) for making a form lock with the power supply module (11) is located in the end region, remote from the introduction opening of the guide sleeve (15). The power supply module (11) has a module housing (13), which receives a battery and an introduction dome (14), formed integrally onto the module housing, for guiding the tool, on which dome there is an electrical interface with the electric power tool and at least one form-locking element for making a form lock with the tool housing (15) is located (FIG. 2).