Abstract: An electrostatic discharge protection circuit device is disclosed, which comprises a first electrostatic discharge protection circuit connected between a first external terminal and a first ground terminal, a second electrostatic discharge protection circuit connected between a second external terminal and a second ground terminal, the second electrostatic discharge protection circuit having substantially the same configuration as that of the first electrostatic discharge protection circuit, a trigger signal line which connects to each other output nodes of surge detection circuits of the first and second electrostatic discharge protection circuits, and transfers a surge detection output of the first or second electrostatic discharge protection circuit to the other electrostatic discharge protection circuit as a trigger signal, and a common discharge line connected directly to the first ground terminal, connected to the second ground terminal via a parallel circuit composed of a forward-connected parasitic di