A fixing device includes a rotatable, endless flexible belt, an elongated stationary pad, a rotatable pressure member, a rotary driver, a releasable biasing mechanism, a first guide member, and a second guide member. The endless flexible belt is looped into a generally cylindrical configuration. The elongated stationary pad is stationarily disposed inside the loop of the belt. The rotatable pressure member is disposed parallel to the stationary pad with the belt interposed between the pressure member and the stationary pad. The rotary driver is operatively connected with the pressure member to impart torque to the pressure member. The releasable biasing mechanism is operatively connected with the pressure member to apply a releasable pressure to the pressure member against the belt in a load direction. The first guide member defines a first elongated opening. The second guide member defines a second elongated opening.