Fixing unit and image forming apparatus

A fixing unit comprising:

• 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 support 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 which makes a separation position where the fixing member leaves the pressure member, farther from the fixing portion in accordance with a thickness of the recording medium, and which increases an angle between a tangent line direction of the pressure member and the fixing member in the separation position.