An image forming apparatus includes a main assembly, a first openable member openably and closably provided in the main assembly, a second openable member openably and closably provided in the main assembly, and a fixing unit for fixing a toner image formed on a recording material in the main assembly, with the fixing unit including a pressure applying mechanism for applying a pressure to a fixing nip of the fixing unit. In addition, a first arm transmits a first operation force, generated when the first openable member is opened by the operator, to the pressure applying mechanism to release the pressure applied to the fixing nip, and a second arm transmits a second operation force, generated when the second openable member is opened by the operator, to the pressure applying mechanism to release the pressure applied to the fixing nip. The fixing unit is detachably mountable relative to the main assembly and includes a pressure switching member, engaged to the pressure applying mechanism, to receive the first operation force via the first arm when the first openable member is opened and to move the pressure applying mechanism, and the second operation force generated when the second openable member is opened is transmitted to the pressure switching member.