A card processing device including an insertion/ejection port through which a card is inserted and ejected, a conveyance path through which the inserted card is conveyed to a predetermined position, a magnetic head provided on the conveyance path and reading magnetic information of the card by conveying the card, and a control unit which is configured to control the conveyance of the card and the reading of the magnetic information, wherein the control unit is configured to read or write information of the card characterized by sequentially performing processings including: a first intermittent conveyance processing in which the inserted card is intermittently conveyed until the inserted card passes through the magnetic head and then the inserted card is intermittently conveyed until the inserted card passes through the magnetic head in a direction towards the insertion port; a magnetic data reading and writing processing in which the card is conveyed at a constant speed from the insertion port toward an inside of the card processing device such that the magnetic head reads or writes the magnetic information of the card; and a second intermittent conveyance processing in which the card is intermittently conveyed until the card passes through the magnetic head in a direction from the inside of the card processing device toward the insertion port and then the card is intermittently conveyed until the card passes through the magnetic head in reverse direction. wherein the control unit is configured to read or write information of the card characterized by sequentially performing processings including: a first intermittent conveyance processing in which the inserted card is intermittently conveyed until the inserted card passes through the magnetic head and then the inserted card is intermittently conveyed until the inserted card passes through the magnetic head in a direction towards the insertion port; a magnetic data reading and writing processing in which the card is conveyed at a constant speed from the insertion port toward an inside of the card processing device such that the magnetic head reads or writes the magnetic information of the card; and a second intermittent conveyance processing in which the card is intermittently conveyed until the card passes through the magnetic head in a direction from the inside of the card processing device toward the insertion port and then the card is intermittently conveyed until the card passes through the magnetic head in reverse direction. a first intermittent conveyance processing in which the inserted card is intermittently conveyed until the inserted card passes through the magnetic head and then the inserted card is intermittently conveyed until the inserted card passes through the magnetic head in a direction towards the insertion port; a magnetic data reading and writing processing in which the card is conveyed at a constant speed from the insertion port toward an inside of the card processing device such that the magnetic head reads or writes the magnetic information of the card; and a second intermittent conveyance processing in which the card is intermittently conveyed until the card passes through the magnetic head in a direction from the inside of the card processing device toward the insertion port and then the card is intermittently conveyed until the card passes through the magnetic head in reverse direction.