A skin treatment device (100) comprises: —a housing (101) —a treatment action performer (110) arranged within the housing (101) for performing a treatment action on the users skin (2) through an output window (103) —a speed sensor (120) for sensing a relative speed between the housing and the users skin —a control device (140) provided with an associated memory (141) containing information defining a desired displacement speed, the control device receiving an output signal from the speed sensor —an optical speed deviation indicator system (400 600) comprising a position reference (411 101) and means for generating an optical spot (412 612) of variable position with respect to the position reference. The control device controls the optical speed deviation indicator system on the basis of the output signal received from the speed sensor and the information in its memory.
