An image reading apparatus which reads an image on a target includes a first housing, a transparent member which is provided on the first housing and has a placement face on which the target is placed, a positioning member on which the transparent member is placed, a second housing which is assembled on the first housing and biases the positioning member, and an engagement member which is provided on the second housing and engages with the positioning member. In the image reading apparatus, when the second housing is assembled on the first housing, the engagement member biases the positioning member so as to fix the transparent member to an attachment position.