Card reader and foreign matter detection method

A card reader for use with a card, the card reader comprising:

• a magnetic detector structured to detect magnetism from the card inserted into an insertion port;
• a main body part comprising a card conveyance path in which the card inserted from the insertion port is conveyed;
• and
• a card detection sensor disposed in the main body part and structured to detect a tip end of the card in an insertion direction of the card, wherein
• the magnetic detector and the card detection sensor are disposed at a distance less than a length of the card in the insertion direction,
• the card reader further comprising a control unit structured to start monitoring of the magnetism detected by the magnetic detector when the card detection sensor detects a tip end of an insert inserted into the insertion port, and detect that an object other than the card has been inserted when a movement distance of the insert in a period in which the magnetism is undetected by the magnetic detector is a predetermined value or more.