A device for molding foodstuff masses comprises: one or more molds (14) provided with sockets (16) which define pouring cavities; inserts (22) made of thermally conductive material associated, in a relationship of heat exchange, with the pouring cavities (16); and thermal-conditioning units (24), such as Peltier cells, associated to the inserts made of thermally conductive material (2). There is present a control unit (34) for generating signals for control of the thermal-conditioning units (24) so as to provide cycles of thermal treatment of the material undergoing selectively pre-determined pouring.A preferential application is in the sector of the confectionery industry.