An image forming device includes a casing, photosensitive bodies, developing devices, developer accommodating devices, and a retaining member. The developer accommodating devices includes a first developer accommodating device that is individually replaceable and separable from the corresponding developing device and a second developer accommodating device that is replaceable together with the corresponding developing device. The retaining member retains the photosensitive bodies arranged in an arrangement direction, the developing devices, and the developer accommodating devices at fixed positions within the casing. The retaining member is capable of being pulled out from the casing and is movable between a housed position and a withdrawn position. One of the developer accommodating devices located at a most downstream side in the arrangement direction is the first developer accommodating device, and each of the developer accommodating devices other than the one of the developer accommodating devices is the second developer accommodating device.