A medium processing device includes: a cylindrical drum; an inner tape that is withdrawn from an inner reel and are wound onto the drum; an outer tape that is withdrawn from an outer reel and are wound onto the drum together with the inner tape with a paper medium interposed therebetween; a contrasting region that has contrasting physical properties, and that is formed at a terminal-end portion of at least one of the tapes; a detection section that detects the physical properties on a contrasting tape that is one of the tapes formed with the contrasting region; and a controller that controls rotation of the drum based on a detection result of the detection section, wherein a normal tape that is one of the tapes not formed with the contrasting region, has a length that is longer than that of the contrasting tape by an additional length.