A cooler for cooling particulate material which has been subjected to heat treatment in an industrial kiln, such as a rotary kiln for manufacturing cement clinker, which cooler comprises an inlet, an outlet, end walls, side walls, a bottom and a ceiling, at least one stationary supporting surface for receiving and supporting the material to be cooled, means for injecting cooling gas into the material, as well as a reciprocating scraper system which comprises a number of rows of scraper elements which extend transversely across the direction of movement of the material, said elements being moved back and forth in the direction of movement of the material in order to convey the material forward over the supporting surface, characterized in that each row of the transverse scraper elements is firmly fixed to at least one drive plate oriented in the direction of movement of the material, and in that said plate extends at least across the entire length of the supporting surface, and in that said drive plate is led either through the supporting surface, the ceiling, one of the side walls and/or at least one of the end walls of the cooler, where the drive plate is connected to a drive arrangement for movement back and forth.