In an electrically operated hand mixer (10) including an attachment (1), the latter is provided with a bowl (2) closable by a lid (9). The hand mixer has at least two first (90) and second (77) drive shafts adapted for detachable coupling with various processing tools (76), such as whisk attachments or kneading blades. One of the drive shafts (90) can be non-rotatably coupled with an output shaft (16), extending upwardly through the lid (9), when the hand mixer (10) is placed on the lid (9) of the attachment (1). The output shaft (16) is connected with a drivable blade (21, 22) in the interior of the bowl (2) for chopping foods. The non-rotatable connection is established by engagement of a first toothing (71) provided in the drive shaft (90) and a mating second toothing (70) provided on the output shaft (16). The drive shaft and/or output shaft (90, 16), according to the present invention, is axially displaceable in opposition to the force of a spring (67) so that, during installation, the hand mixer (10) will move into abutment on the lid (9) even in the absence of an engagement between the first (71) and second (70) toothings. This permits ease of coupling of the hand mixer (10) to the attachment (1) because automatic coupling engagement of the drive and output shafts (90, 16) takes place as soon as the motor starts to operate.