A card reader has a main body and a card reader unit provided within the main body for executing at least one of recording and reproducing data on a card inserted in the card reader unit. A first communication unit is provided within the main body for executing at least one of inputting and outputting a signal, a power supply unit is provided within the main body for supplying electric power to each unit, and a controller is provided within the main body for controlling each unit. An accessory device can be removably attached to the main body for having at least one of the functions among a printing function, a data communicating function and a display function. A second communication unit is provided within the accessory device for having at least one of the functions of receiving a signal from the first communication unit and sending a signal to the first communication unit.