A fixing device (20) includes a support member (25) disposed to support a nip formation member on an inner peripheral surface of a fixing belt (21). The support member includes a parallel portion (25a) that supports the nip formation member (24) and extends parallel to a sheet transport direction in a nip portion, and a rise portion (25b) that extends from the parallel portion in a direction drawn apart from the nip portion. The rise portion is inclined to the parallel portion such that an inclination direction of the rise portion is substantially parallel to a virtual straight line (L) connecting a center of rotation (X) of the fixing belt and an inlet point (Y) of the nip portion or falls within a range of rotational angles of ± 15° by which the virtual straight line is rotated around the center of rotation of the fixing belt.
