1. A biological light measurement device including a light source unit that irradiates near-infrared light, a two-dimensional probe that measures a transmitted light intensity of the near-infrared light at two-dimensional measurement points of a subject body and outputs a signal corresponding to the transmitted light intensity at each measurement point as measurement data for every measurement channel, a signal processing unit that processes the measurement data of the two-dimensional probe to be imaged, and a display unit that displays the imaged measurement data, the biological light measurement device comprising: a storage unit that stores data regarding a head shape for display; and a control unit having a coordinate transformation section which performs coordinate transformation of positional information of the two-dimensional probe, which is set on a two-dimensional head image selected from the data regarding the head shape, in order to calculate a light irradiation position and a light detection position on a three-dimensional head image or the position of the measurement channel.