A detection unit includes multiple detection elements, which are configured to output intensities of received light as detection signals, and a light shielding portion, which is configured to regulate an incident angle of light with respect to the detection elements. The storage unit is configured to store a reference distribution indicating a distribution of intensity of light detected with the detection units caused by irradiation of reference light having a reference directivity characteristic on the detection unit. The calculation unit is configured to input the detection signals from the detection elements, to calculate the detection distribution of the intensity of received light, to input the reference distribution from the storage unit, to calculate a deviation of the detection distribution from the reference distribution, and to calculate a directivity characteristic of received light on the basis of the deviation.