A protection circuit protects a semiconductor device provided on a semiconductor substrate and including an interconnect from charge entering the interconnect during fabrication of the semiconductor device. The protection circuit includes a first metal interconnect connected to the interconnect; a forward diode and a backward diode connected in parallel to the interconnect; an NMIS whose drain is connected to the output port of the forward diode, whose source is connected to the semiconductor substrate and whose gate is grounded through an upper metal interconnect; a PMIS whose drain is connected to the input port of the backward diode and whose source is connected to the semiconductor substrate; a first antenna connected to the gate of the NMIS; and a second antenna connected to the gate of the PMIS.