Building material cutting device

The utility model is applicable to the technical field of angle grinders, and provides a building material cutting device which comprises an angle grinder main body and a fixing ring block, the angle grinder main body is provided with a machine body, a head shell and an output rotating shaft, the fixing ring block is located on the outer side of the output rotating shaft, and a protection assembly used for protecting a saw blade is installed on the outer side of the fixing ring block. According to the angle grinder, the safety lock assembly and the protection assembly are arranged, when the protection assembly is not installed, the telescopic sleeve and the fixed gear are connected in a clamped mode, at the moment, the fixed gear is limited and cannot rotate, namely the output rotating shaft cannot rotate, and the effect that the angle grinder cannot be used when the protection assembly is not installed can be achieved; when the protection assembly is installed, the telescopic sleeve is extruded to be shrunk