To provide a device for machining pieces with the aid of a laser beam, a device in which the position of two reflection mirrors can be easily changed particularly with flexibility.

The device for machining pieces with the aid of a laser beam comprises a chassis, a laser (2; 52) adapted to emit a laser beam (f1), a first reflecting mirror (8; 58; 108) placed on the path of the emitted beam (f1) in order to reflect an intermediate beam (f2), and a second reflecting mirror (12; 62; 112) placed on the path of the intermediate beam so as to direct a machining beam (f3) towards the pieces to be treated. The device further comprises means for displacing the first and second reflecting mirrors with respect to the chassis, such displacement means comprising at least one principal linear motor (4, 10; 54, 60; 104, 110).