A bearing structure reduces friction between a roller and a bearing under a pressure. A fusing device for an image forming apparatus employs the bearing structure. The bearing structure installed between a frame and a rotary shaft supports the rotary shaft on the frame. A bearing body has a fitting part in which the rotary shaft is rotatably fitted. A rolling support unit is installed on at least one portion inside the fitting part to contact the rotary shaft in a rolling manner. The fusing device includes a fusing roller in which a heater is embedded, and a pressure roller that faces the fusing roller and cooperates with the fusing roller in pressing a sheet of paper passing therebetween. Bearing structures rotatably support the fusing roller and the pressure roller on a frame. Each bearing structure includes a bearing body having a fitting part, and a rolling support unit installed on at least one area inside the fitting part to contact the fitted roller in a rolling manner.