The present invention relates to a surgical knife that is characterized in that the cutting edge (1) thereof is provided with a cover (2) that is attached by means of an arresting screw (4) to a holder (3), which is coupled with the cutting edge (1). The cover (2) slidable and at the working portion of the cutting edge (1) it is provided with a guide collar (5), wherein thee holder (3) is provided with guide marks (6). The surgical knife of the present invention enables exact and regular depth and incline for the entire cut and optionally the cut can be exactly repeated, too.