A gate driver IC includes: N shift registers which generate a gate signal to be supplied to a display panel substrate, N being a natural number; (N+k) power supply terminals (PA1 to PD1, Pa1, and Pc1) for power supply from outside, k being a natural number; and (N+k) internal lines connected to the (N+k) power supply terminals, wherein N internal lines among the (N+k) internal lines connect, one-to-one, N power supply terminals among the (N+k) power supply terminals and the N shift registers, and k internal lines other than the N internal lines among the (N+k) internal lines connect, one-to-one, k power supply terminals other than the N power supply terminals among the (N+k) power supply terminals and k internal lines selected from among the N internal lines.