A roller assembly including a shaft, a first support body to which one end of the shaft is coupleable, a second support body to which another end of the shaft is coupleable, and a roller coupleable between the first support body and the second support body, having a cylindrical shape in which the shaft is insertable, and rotatably supported by the shaft. The first support body and the second support body respectively include a protrusion that protrudes toward side surfaces of the roller, the protrusion of the first support body and the second support body respectively protrude from the first support body and the second support body and are respectively insertable into spaces inside an outer circumference of the roller, and the roller includes accommodation grooves on both side surfaces of the roller and accommodate the protrusion of the first support body and the second support body with certain gaps, respectively.