An image reading apparatus includes: a light source that irradiates a document; a sensor that receives reflection light reflected from the document; a reference member that is read by the sensor; and an abnormal site detection unit that detects, using first reading data acquired by reading the reference member according to a first reading condition set to the light source or the sensor and second reading data acquired by reading the reference member according to a second reading condition, which is different from the first reading condition, set to the light source or the sensor, abnormal sites in the first reading data or the second reading data.