Abstract: Method for controlling the direction of a drilling device which drills a hole into a ground wherein a hammering and rotatable bit (3) is used as the drilling bit and the device comprises coupled with the bit (3) a hammering device (2) behind the bit (3) and a drill arm which is potentially related to it wherein the rear part (15) of the hammering device or the drill arm locates in the drilled hole or inside a casing tube (1) which covers the drilled hole in a free space so that there is space for the mentioned rear part (15) to move in the direction of the radius of the drilled hole and that the location of the bit (3) in the ground during the drilling is observed on the grounds of the data received from the position sensors which indicate the location of the bit (3), characterized in that in the method the direction of the drilling is steered by adjusting only the position of the mentioned rear part (15) in relation to the center line (C) of the drilling by organizing a support, which is deviated from the ce