The disclosed invention reduces an increase in the number of electrostatic discharge protection circuits or the number of electrostatic discharge protection elements due to increases in the number of separations of power voltages and the number of separations of ground voltages. A semiconductor integrated circuit includes first, second, and third operation voltage supply terminals; first, second, and third internal circuits; first, second, and third electrostatic discharge protection circuits; and a coupling midpoint. The first, second, and third internal circuits operate at first, second, and third operation voltages supplied to the first, second, and third operation voltage supply terminals, respectively. The first, second, and third electrostatic discharge protection circuits are coupled between the first, second, and third operation voltage supply terminals and the coupling midpoint, respectively. That is, instead of the past Δ (delta) coupling, the first, second, and third electrostatic discharge protection circuits are Y (star)-coupled with respect to the coupling midpoint.