A fixing device has first and second rollers respectively formed of a metallic cylindrical body provided with an elastic member. The rollers are abutted against each other so that the elastic members contact each other. The fixing device further has a heater for heating at least one of the rollers and a driver for rotating at least one of the rollers so that a transfer sheet passes through contact portion of the rollers. Roller hardness of the first roller is smaller than that of the second roller, and density of cross-link of the elastic member of the first roller is lower than that of the elastic member of the second roller.