The present invention relates to a boring head constituted by a body (1) provided with a radial piston (2) for reception of a boring tool (3) gripped by means of a screw (4), said piston (2) being adjustable in position by means of a micrometric screw (5), characterized in that the body (1) is provided also with a slide block (6) effecting the guidance, the orientation and an end-of-movement abutment for the piston (2) for reception of the boring tool (3) and with a balancing device (7) with independent counterweights (8 and 9).