The purpose of the present invention is to allow a silicon photonics modulator to be operated at high speed with high frequency by providing an electrode structure for the small multichannel high-density silicon photonics modulator. This electrode structure for a silicon photonics modulator includes, on the planar surface of a silicon substrate, a first layer for forming a plurality of bias electrical wirings, and a second layer formed by aligning each of a plurality of ground electrode portions and each electrical wiring in the first layer.