The device (1) has a climbing unit (3) that is connected with a carrier unit (2) and provided with climbing elements (4,5). The climbing elements are driven by a drive motor (6) and formed with stairway steps (11,12). The climbing unit is driven with different drive speeds. The drive speed is lowered to predetermined drive speed before placing the climbing element on the nearest stairway step so that the smooth fitting is ensured. The drive speed is adjusted to a speed different from predetermined drive speed after placing the climbing element on nearest stairway step. An independent claim is included for method for operating climbing unit of staircase climbing device.
