A control system includes a controlled apparatus and a portable terminal apparatus that controls the controlled apparatus. The controlled apparatus includes an authentication code generating unit that generates an authentication code and an authentication code output unit that outputs the generated authentication code. The portable terminal apparatus includes a code input unit that inputs a code and a code transmitting unit that transmits the input code to the controlled apparatus. The controlled apparatus further includes a determining unit that determines whether the code transmitted from the code transmitting unit is the authentication code output from the authentication code output unit and whether a first period has elapsed since generation of the authentication code and a permission unit that permits control using the portable terminal apparatus in response to determination that the transmitted code is the output authentication code and the first period has not elapsed.
