A method for regulating the traction in a line (13) of a ladder climbing assistance device, in which method any movement of the line (13) is sensed and in dependence of the sensed movement either increasing the traction in the line to a predetermined high level (L1), maintaining the traction at a predetermined high level (L1), or decreasing the traction to a predetermined low level (L0). Furthermore, a ladder climbing assistance device comprising a line (13) that is movable along the ladder (1) and a motor (8) with a power outlet arranged to provide an essentially constant traction in the line (13). The ladder climbing assistance device comprises sensing means (25) for sensing any movement of the line (13), which sensing means is connected to controlling means (26) for controlling the power outlet from the motor (8) in response to signals from the sensing means in the above-described manner.