There is disclosed a probe holder module that configures apart of a probe holder for an optical measurement which holds a light emission probe and a light detection probe and can be mounted on an object to be measured and configures the probe holder for optical measurement by combining a plurality of probe holder modules, the probe holder module including a holding part for mechanically holding at least one of the light emission probe and the light detection probe, at least one of an electric circuit and electric wiring to be electrically connected to at least one of the light emission probe and the light detection probe, a terminal for connecting at least one of the light emission probe and the light detection probe and at least one of the electric circuit and the electric wiring, a mechanical connection part to be mechanically connecting other probe holder module, and an electrical connection part to be electrically connected to the other probe holder module.
