A sanding machine for sanding panels, including a supporting structure, a sanding unit supported by the supporting structure, a surface for supporting and sliding of the panels located beneath the sanding unit and along which the panels are fed in a predetermined feed direction; the sanding unit including a trestle supporting a sanding belt, the trestle including a plurality of rollers having respective axes parallel to the supporting surface, the sanding belt being endless and looped around the rollers, one of the rollers being motorized to move the sanding belt during the sanding of the panels, the sanding unit further including at least one opposing member to force the belt against the panel to be sanded.