An image reading apparatus includes a light source unit, an image sensor, and a light guiding unit at least including a light reflector. The light guiding unit may include a first masking shield and a second masking shield. The light source unit irradiates light toward an original. The image sensor picks up an image of the original based on reflected light of the light by the original. The light guiding unit is provided on an opposite side to the light source unit to cause a part of the light to directly enter into the image sensor, when the original is not fed to the image sensor. The light guiding unit reduces light incident to the image sensor, among the light and light having transmitted through the original, at the time of picking up the image of the original by the image sensor.