PURPOSE: To provide the medium processor which can stably read information out of a magnetic stripe and record information on the magnetic stripe by a simple mechanism.

CONSTITUTION: A medium fall preventive guide 12 is fitted to one end of a link 14. In the link 14, a long hole 13 which is parallel to the travel direction of a magnetic head 10 is formed and a projection part 17 which abuts against a holder 19 supporting the magnetic head 10 is formed at the other end. In the long hole 13, a post 21 is loosely fitted which restricts the movement range of the link 14. Then the other end of a spring 20 having one end fitted to a frame 16 is fitted to the fall preventive guide 13, and the projection part 17 is made to follow up the movement of the magnetic head 10.