A card reader which reads or writes data from or to a card inserted through a card insertion port into a card reader body via a card transport path is described the card reader comprises a shutter provided near the card insertion port to open or close the card transport path. A first detector is provided for detecting the card inserted therein near a first end of the card insertion port. A sensor is provided for detecting a change in the first detector. A locking member of the card reader is capable of switching positions of the shutter between an open-position and a close-and-lock position. A controller is provided for controlling switching positions of the locking member between the open position and the close-and-lock position of the shutter. A second detector is provided at a second end of the card insertion port, which is capable of switching states of the locking member between a stationary mode and a movable mode such that when the card is inserted into A card insertion port, the second detector sets the locking member in the movable mode and the controller starts up based on the sensor output to move the locking member to the open position of the shutter to allow the shutter to be opened or closed.