A transfer unit of an electrophotographic printer, includes a base frame; a first lever which is pivotally installed at the base frame, and by which a transfer roller is supported, the transfer roller rotating while closely contacting a photosensitive belt and to which an image on the photosensitive belt is transferred; and a second lever which is pivotally installed at the base frame, and by which a fixing roller is supported, the fixing roller pressing a paper passing through between the transfer roller and the fixing roller against the transfer roller while rotating in contact with the transfer roller, and fixing an image on the transfer roller onto the paper. A first elastic biasing mechanism is provided for elastically biasing the first lever and the second lever so that the transfer roller and the fixing roller can be separated from each other; a second elastic biasing mechanism is provided for elastically biasing the first lever so that the transfer roller can separate from the photosensitive belt; and a wire is provided one end of which is fixed to a winding gear rotatably installed at the base frame, and the other end of which is fixed to the first lever, and which is connected to the first lever and the second lever so that the transfer roller and the fixing roller, and the photosensitive belt approach each other while overcoming the elastic biasing forces of the first and second elastic biasing mechanisms.