To provide a high frequency matrix circuit which is light in weight and small in size and is suitable to the large scale of signals and is capable of processing high frequency signals of wide range by converting high frequency signals into optical signals and by reconverting the optical signals into electric signals while performing distributions and synthesizes and the setting of phases of signals.

High frequency signals are inputted from either of input ports 1011∼1018 and are respectively converted into optical signals by EO conversion means 1131∼1138 Then, outputs of the EO conversion means 1131∼1138 are inputted to an optical planar circuit 14. The signals propagate in the optical planar circuit 14 while being received with distributions and the settings of phases. The TE waves (local oscillation) and the TM waves (signal light) are synthesized by an analyzer 109 to be inputted to OE converters 1161∼1168. Moreover, high frequency signals having the same frequencies as those of the input signals are taken out as beat lights between the signal lights and the local oscillation lights in the OE converters 1161∼1168.