An image forming apparatus that is orientatable in either a first position or a second position, the second position being different from the first position in inclination with respect to a horizontal plane, comprising: a fixing unit including a heating roller and a pressurizing member, wherein the fixing unit is arranged to press the pressurizing member against a surface of the heating roller to form a fixing nip, and to thermally fix a toner image formed on a recording sheet passing through the fixing nip; at least one temperature detector arranged to detect temperature of the surface of the heating roller without contact with the surface; a heater arranged to heat the heating roller; and a controller arranged to control the heater according to the temperature detected by the at least one temperature detector, and thereby control the temperature of the surface of the heating roller, and a switcher (50, 51, 232, 230) arranged to switch a detection point of the at least one temperature detector between a first detection point and a second detection point according to whether the image forming apparatus is in the first position or in the second position, a storage arranged to store a first correction table corresponding to the first position and a second correction table corresponding to the second position; and an acquirer arranged to acquire orientation information indicating whether the image forming apparatus is in the first position or in the second position, characterised in that: the detection point is located above a horizontal plane passing through a rotational axis of the heating roller regardless of whether the image forming apparatus is in the first position or in the second position, and in that: the controller is arranged to select either the first correction table or the second correction table whichever corresponds to the orientation information acquired by the acquirer, and to control the temperature of the surface of the heating roller by using either the first correction table or the second correction table whichever is selected by the controller and the temperature detected by the at least one temperature detector. a fixing unit including a heating roller and a pressurizing member, wherein the fixing unit is arranged to press the pressurizing member against a surface of the heating roller to form a fixing nip, and to thermally fix a toner image formed on a recording sheet passing through the fixing nip; at least one temperature detector arranged to detect temperature of the surface of the heating roller without contact with the surface; a heater arranged to heat the heating roller; and a controller arranged to control the heater according to the temperature detected by the at least one temperature detector, and thereby control the temperature of the surface of the heating roller, and a switcher (50, 51, 232, 230) arranged to switch a detection point of the at least one temperature detector between a first detection point and a second detection point according to whether the image forming apparatus is in the first position or in the second position, a storage arranged to store a first correction table corresponding to the first position and a second correction table corresponding to the second position; and an acquirer arranged to acquire orientation information indicating whether the image forming apparatus is in the first position or in the second position, characterised in that: the detection point is located above a horizontal plane passing through a rotational axis of the heating roller regardless of whether the image forming apparatus is in the first position or in the second position, and in that: the controller is arranged to select either the first correction table or the second correction table whichever corresponds to the orientation information acquired by the acquirer, and to control the temperature of the surface of the heating roller by using either the first correction table or the second correction table whichever is selected by the controller and the temperature detected by the at least one temperature detector.