An image forming apparatus comprising: a fixing unit including a rotary fixing member and a rotary pressing member, configured to fix a toner image on a sheet by causing the sheet carrying the toner image to pass through a nip portion formed by bringing the rotary fixing member and the rotary pressing member into pressure contact with each other; an image forming apparatus main body including a fixing unit accommodating portion that accommodates the fixing unit in an insertable and removable manner; and a heating unit provided in the image forming apparatus main body and configured to heat the rotary fixing member of the fixing unit mounted in the fixing unit accommodating portion (2c-2e) from a side opposite to the nip portion side, wherein the image forming apparatus further comprises: a drive unit configured to move the heating unit between a heating position set in advance so as to be able to heat the rotary fixing member of the fixing unit mounted in the fixing unit accommodating portion and a retracted position at which the heating unit is moved outward in a radial direction of the rotary fixing member from the heating position and retracted outward from an insertion/removal path of the fixing unit; and an operation unit operable by a user, wherein an insertion/removal direction in which the fixing unit is inserted into and removed from the fixing unit accommodating portion coincides with an axial direction of the rotary pressing member, and wherein the drive unit is configured to be capable of selectively switching a position of the heating unit between the heating position and the retracted position in conjunction with an operation of the operation unit. a fixing unit including a rotary fixing member and a rotary pressing member, configured to fix a toner image on a sheet by causing the sheet carrying the toner image to pass through a nip portion formed by bringing the rotary fixing member and the rotary pressing member into pressure contact with each other; an image forming apparatus main body including a fixing unit accommodating portion that accommodates the fixing unit in an insertable and removable manner; and a heating unit provided in the image forming apparatus main body and configured to heat the rotary fixing member of the fixing unit mounted in the fixing unit accommodating portion (2c-2e) from a side opposite to the nip portion side, wherein the image forming apparatus further comprises: a drive unit configured to move the heating unit between a heating position set in advance so as to be able to heat the rotary fixing member of the fixing unit mounted in the fixing unit accommodating portion and a retracted position at which the heating unit is moved outward in a radial direction of the rotary fixing member from the heating position and retracted outward from an insertion/removal path of the fixing unit; and an operation unit operable by a user, wherein an insertion/removal direction in which the fixing unit is inserted into and removed from the fixing unit accommodating portion coincides with an axial direction of the rotary pressing member, and wherein the drive unit is configured to be capable of selectively switching a position of the heating unit between the heating position and the retracted position in conjunction with an operation of the operation unit. a drive unit configured to move the heating unit between a heating position set in advance so as to be able to heat the rotary fixing member of the fixing unit mounted in the fixing unit accommodating portion and a retracted position at which the heating unit is moved outward in a radial direction of the rotary fixing member from the heating position and retracted outward from an insertion/removal path of the fixing unit; and an operation unit operable by a user, wherein an insertion/removal direction in which the fixing unit is inserted into and removed from the fixing unit accommodating portion coincides with an axial direction of the rotary pressing member, and wherein the drive unit is configured to be capable of selectively switching a position of the heating unit between the heating position and the retracted position in conjunction with an operation of the operation unit.