An image forming apparatus includes an upper cover attached to a main body, an image forming part provided in the main body and configured to record an image on a sheet, an image reading part having a document press member, and a lock mechanism. The upper cover is configured to be pivotable on a support axis with respect to the main body. The image reading part is slidably mounted on the upper cover. The document press member is configured to open and close with respect to a housing of the image reading part in a direction similar to a direction in which the upper cover opens and closes. The lock mechanism is configured to prevent the document press member from opening over a slidable range of the image reading part when the upper cover is opened.