A fixing unit includes: a support member; an endless-belt-like fixing member which is wound on the support member; a pressure member which rotates in a fixed rotation direction while being pressed onto the fixing member; a fixing portion in which the fixing member and the pressure member abut against each other to perform fixation on a recording medium; a separation unit which is provided in a space between the support member and the fixing member on a downstream side of the fixing member in a rotation direction of the fixing member and for separating the recording medium from the fixing member; a separation portion which is provided in the separation unit to press the fixing member onto the pressure member and guide the fixing member to leave the pressure member; and an adjustment unit as defined herein.