At least one developing device applies toner onto a latent image formed on an image supporter to form a toner image thereon. A belt member is stretched and circulated by a plurality of roller members. The toner image, which is to be secondarily transferred onto a recording medium, is primarily transferred onto the belt member. A fixing device heats the recording medium to fix the secondary transferred toner image thereon. A casing accommodates the image supporter, the developing device, the roller members, the belt member and the fixing device, such that the developing device and the fixing device are partitioned by the belt member, and such that one of the roller members is located at a corner portion of the casing.