To provide an electronic key capable of easily checking whether or not data has been read from a contact IC chip and enhance reliability of security, an electronic key includes a contact IC chip connected in series to first and second terminals so that data is read from the IC chip by a current allowed to flow between the first and second terminals, wherein the electronic key comprises an LED arranged in parallel to the contact IC chip and allowed to turn on through use of the current allowed to flow between the first and second terminals when the first and second terminals contact with IC chip data reading means, and turn-on of the LED indicates that data has been read from the contact IC chip.