A roller for a belt conveyer. A roller tube has an engraved groove for indicating the degree to which the surface of the roller is abraded. A shaft reinforcement member is provided in one end of the roller tube, connected to a shaft disposed inside the roller tube, and rotatably coupled to the belt conveyor. A dustproof cover closes one end of the roller tube, and the shaft reinforcement member extends through the dustproof cover. A bearing housing is fitted into the dustproof cover, with a bearing thereof being rotatably coupled to the outer circumference of the shaft reinforcement member. A flat spring is fitted into the bearing housing, and elastically supports one surface of the bearing, thereby controlling expansion or contraction of the bearing. An end cap is fixedly coupled to an outer surface of the dustproof cover in order to block impurities from entering the roller.