A lighting device used in an image forming apparatus includes point light sources (32) that emits rays; and a condensing body (33) that is arranged in a direction of the rays emitted from the point light source (32) and that condenses the rays on a surface of a document, which is placed on a contact glass (12), within a reading width in a sub-scanning direction of the document. The condensing body (33) is arranged in a direction in which angles of all rays, which pass through the condensing body (33), are smaller than a critical angle of total reflection on the contact glass (12).