An image forming apparatus has a holding member having a plurality of photosensitive drums and configured to hold a plurality of toner cartridges in a detachable manner. The holding member is coupled to an apparatus body in a tiltable manner between a storage position where the holding member is disposed in the apparatus body substantially horizontally and a replacement position where the holding member is raised from the apparatus body substantially vertically. A top cover supports a plurality of light source arrays in association with the photosensitive drums and is coupled to the apparatus body in a tiltable manner between a closed position where the light source arrays are positioned with respect to photosensitive drums and an open position where the light source arrays are withdrawn from the photosensitive drums. The top cover tilts in a different direction from a direction that the holding member tilts.