PURPOSE: To reduce the generation of image omission and wrinkle due to the expansion of a pressurizing roller by the heat of a heating roller.

CONSTITUTION: The heating roller of a heat roller fixing device is rotated by a driving device. When a transfer material is of size A2, A3, an electromagnetic clutch 37 is ON. Consequently, the rotating force of a motor 31 is transmitted to a shaft 25a through one gear 32 out of a double gear and a gear 35, and the heating roller is rotated at the first speed. When the transfer material is of size A0, A1, the electromagnetic clutch 37 is OFF. Consequently, the rotating force of the motor 31 is transmitted to the shaft 25a through the other gear 33 out of the double gear and a gear 34, and the heating roller is rotated at the second speed slower than the first speed. Since the carrying speed by the heating roller 25 is set to a proper value according to the width of the transfer material, the generation of image omission and wrinkle is reduced.