In an image forming apparatus, a cartridge has a cartridge side electrode. A main casing has a main casing side electrode. The cartridge includes a moving member that allows the main casing side electrode to be located at a connection position when the moving member is at a first position, to be located at a disconnection position when the moving member is at a second position, and to be located at the connection position when the moving member is at a third position. A determining unit determines that the cartridge's state is new if the determining unit detects that the main casing side electrode is electrically connected to the cartridge side electrode, then the main casing side electrode is electrically disconnected from the cartridge side electrode temporarily, and then the main casing side electrode is again electrically connected to the cartridge side electrode.