Patent ID: 7239903

Claim:
A brain function measurement device, which uses a light irradiation unit that irradiates examination light toward the inside of a head of a subject, and a light receiving unit that receives the examination light exiting from the head and outputs light intensity signals indicating a light intensity thereof comprising: a structural data storage unit that stores structural data indicating a head structure wherein the head is divided into multiple materials, and the various materials are further divided into multiple elements; an optical properties and hemoglobin parameters calculator that calculates optical properties of the aforementioned elements from predetermined initial values that differs between the various materials, and calculates the hemoglobin parameters inside the brain of the subject based on the optical property values thereof; and an initial values calculator that calculates the aforementioned initial values, characterized in that the initial values calculator thereof provisionally stipulates the optical property values of the various materials under the assumption that the optical properties are uniform for each material, and takes the aforementioned initial values to be the accepted optical properties when the light intensity signal values calculated from these provisional optical properties are in a fixed range of the actually measured light intensity signal values.