A fixing device includes a detecting portion that detects a load applied to a driving portion configured to drive a fixing portion configured to fix an image formed on a medium, an identifying portion that identifies a type of the medium from a result of detection performed by the detecting portion, and a setting portion that sets a threshold with reference to which the identifying portion identifies the type of the medium. The threshold is set for each of different temperatures detected by a temperature detecting portion that detects a temperature of the fixing portion or for each predetermined number of media on which images are fixed.

A sheet feeding apparatus includes a tray on which a plurality of sheets can be stacked, the tray being movable in a vertical direction to lift the sheets, a pickup roller that is rotatable to convey an uppermost sheet of the sheets in a conveyance direction when the sheets are lifted and pressed against the pickup roller, a first guide that is disposed adjacent to the pickup roller and guides the uppermost sheet conveyed by the pickup roller along the conveyance direction, and a pair of lifting members that support the sheets that are stacked in the tray. The lifting members extend along the conveyance direction, are spaced apart in a width direction of the sheets that is transverse to the conveyance direction, and are movable in the vertical direction together with the tray.