an image forming apparatus includes : a main body ; an opening and closing unit disposed so as to be openable and closable for the main body ; a fixing unit fixing the opening and closing unit to the main body ; a structure including a component for realizing an image forming function and / or a transfer medium - conveying function , the structure being supported movably for the main body ; a bias unit disposed between the opening and closing unit and the structure , the bias unit biasing the structure so as to be pushed to a member mounted within the main body ; a constraining unit constraining the opening and closing unit and the structure against a bias force of the biasing unit when the fixing unit does not fix the opening and closing unit ; and a releasing unit releasing the opening and closing unit and the structure from being constrained when the fixing unit fixes the opening and closing unit .