To provide a medium processing device which can be reduced in size while suppressing the deterioration of the reproduction quality or the recording quality of magnetic information.

The medium processing device 1 includes a plurality of carrying roller pairs 14-17 for carrying passage tickets 2; a magnetic head 3 for recording magnetic information to the passage tickets 2 or reading magnetic information recorded on the passage tickets 2; and a printing head 5 for performing printing to the passage tickets 2. The arrangement pitch P1 of the carrying roller pairs 14-17 is set to be smaller than the length of the passage ticket 2 and larger than the length of a magnetic information recording area of the passage tickets 2. The magnetic head 3 is disposed so that the center of the magnetic head 3 is substantially matched with the rotation center of the carrying roller pair 15 in the carrying direction of the passage tickets 2, and the printing head 5 is disposed so that the center of the printing head 5 is substantially matched with the rotation center of the carrying roller pair 16 in the carrying direction of the passage tickets 2.