The invention relates to a method for correcting positioning errors in rock drilling, and a rock drilling equipment. Deviation of the boom position from the theoretical position is measured as a function of the position of at least one boom joint, the measured deviations are stored in the memory of the drilling rig, and when the boom is positioned to the drilling position, its position is corrected on the basis of the stored deviation. The drilling equipment includes a memory for storing the deviations between the true position of the boom and the theoretical position calculated on the basis of the joint sensor values, and a calculating device for correcting the boom position on the basis of the deviations stored in the memory of the drilling rig.