A medium processing device including: a main tape having one end fixed to a drum, and being wound onto the drum while sandwiching a medium with the drum; a first roller at which the main tape unwound from a main reel is turned back at a distant location from the drum; a second roller at which the main tape, turned back by the first roller and travelled along the drum, is separated from the drum and turned back toward the drum, the medium being sandwiched between portions of the main tape turned back by the first and second rollers and being conveyed between the second roller and the drum; an auxiliary tape having one end fixed to a location of the drum that does not overlap with the main tape, and winding the medium onto the drum at least within a separation range of the main tape from the drum.