Abstract: The present invention provides a card slot unit that allows a function extending card having connection electrodes on an insertion-edge side to be inserted into the card slot unit for establishing electrical connection with the card slot unit. The unit comprisesa slot board on which a predetermined wiring pattern is formed;a slot connector which is mounted on the slot board and has connector pins electrically as well as mechanically connectable to the connection electrodes of the function extending card;a card control IC which is mounted on the slot board and electrically connected to the connector pins of the slot connector through the wiring pattern; andan output connector which is mounted on the slot board and electrically connected to the card control IC through the wiring pattern.The card slot unit is hardly affected by noise, reducing the number of errors generated in the signal. As a result, the operating frequency can be raised.