An image-reading apparatus includes a housing having a rectangular-shaped opening on a side of a reading target, a lens portion retained or housed within the housing, and a sensor element to receive light condensed by the lens portion, the light being from the reading target. Long sides of the opening include a first layer that is flat and is disposed on the side of the reading target and a second layer that is continuous with the first layer. The long sides of the opening of the housing of the image-reading apparatus has a flat surface on the side of the reading target and an interface between the first layer and the second layer that is curved.