An image reading apparatus comprising: an apparatus main body including feeding means for feeding a sheet; a first reading sensor provided in a first reading unit and configured to read one surface of the sheet moving along a conveyance path; a second reading sensor provided in a second reading unit provided to face the first reading sensor via the conveyance path and configured to read an image on the other surface of the sheet; a first background portion provided at a readable position of the first reading sensor and serving as a reading background of the first reading sensor; a second background portion provided at a readable position of the second reading sensor and serving as a reading background of the second reading sensor; and a third background portion being a black background portion which is opposite to the second reading sensor in the direction parallel to the conveyance path with respect to the first background portion, a moving portion configured to integrally move the first reading sensor and the second background portion along the conveyance path, wherein the first reading unit includes a sensor case in which the first reading sensor is provided, and the sensor case is fixed to the apparatus main body, and wherein the first reading sensor is able to move between a position where the first reading sensor faces to the first background portion and receives reflection light from the first background portion and a positon where the black background portion which does not have a surface reflecting light to the first reading sensor is placed, characterized in that the third background portion has an inclined surface on the first background portion side, and wherein a position of the black background portion is a position where the first reading sensor faces to the inclined surface. an apparatus main body including feeding means for feeding a sheet; a first reading sensor provided in a first reading unit and configured to read one surface of the sheet moving along a conveyance path; a second reading sensor provided in a second reading unit provided to face the first reading sensor via the conveyance path and configured to read an image on the other surface of the sheet; a first background portion provided at a readable position of the first reading sensor and serving as a reading background of the first reading sensor; a second background portion provided at a readable position of the second reading sensor and serving as a reading background of the second reading sensor; and a third background portion being a black background portion which is opposite to the second reading sensor in the direction parallel to the conveyance path with respect to the first background portion, a moving portion configured to integrally move the first reading sensor and the second background portion along the conveyance path, wherein the first reading unit includes a sensor case in which the first reading sensor is provided, and the sensor case is fixed to the apparatus main body, and wherein the first reading sensor is able to move between a position where the first reading sensor faces to the first background portion and receives reflection light from the first background portion and a positon where the black background portion which does not have a surface reflecting light to the first reading sensor is placed, characterized in that the third background portion has an inclined surface on the first background portion side, and wherein a position of the black background portion is a position where the first reading sensor faces to the inclined surface.