An image forming apparatus which may include an apparatus main body and a module unit. The module unit may include a communication member having an opening that allows communication between inside and outside of the module unit and a unit-side positioning portion located adjacent to the opening of the communication member. Further, the apparatus main body may include a ventilation member having an opening located so as to oppose the opening of the communication member. Further, the apparatus main body may include a main body-side positioning portion located adjacent to an opening of the ventilation member. Also, the apparatus main body may include an urging member that is configured to urge the module unit so as to bring the unit-side positioning portion into contact with the main body-side positioning portion.