Image forming device, exchange unit and method for determining exchange unit

An image forming device includes an attachment part to which a toner unit having a fuse that can be molten by being supplied with an electric current is detachably attached, and a control part that applies each of a non-melting conduction signal corresponding to a first current supply state where the fuse is not molten and a melting conduction signal corresponding to a second current supply state where the fuse is molten to the fuse. The control part detects each of whether or not the fuse is molten by applying the non-melting conduction signal and whether or not the fuse is molten by applying the melting conduction signal. The control part determines whether or not the toner unit attached to the attachment part is a specific exchange unit on the basis of a detection result of whether or not the fuse is molten.