The present invention provides a biological measurement probe readily wearable on a biological surface having a large curvature and a measurement technique of simultaneously measuring the blood circulation dynamic change accompanying the auditory/language/visual function activities of a subject (especially baby) and brain waves. A biological measurement probe having illuminating means for illuminating a subject through a first optical waveguide and light collecting means for collecting light illuminated from the illuminating means and propagated through the subject through a second optical waveguide, has first and second guide members having passages through which the first and second optical waveguides are passed and fixing the first and second optical waveguides, and a base member connecting the first guide member to the second one, holding them, and forming a portion brought into contact with the subject.