An optical image measuring apparatus including: a beam splitter for dividing a light beam into signal light and reference light ; beam splitters for dividing the reference light into plural reference light beams frequency shifters for shifting frequencies of the reference light beams by different amounts; and reflector plates arranged at different distances from an object to be measured. The depot is monitored by the sensor and the depot consists of an absorbent andor swellable material, and is arranged so as to permit delayed leak detection by the sensor. Generated hydrogen is provided via a hydrogen output port formed in the container. The arrays are electrically isolated from each other. This prevents voids with air captured therein due to non-uniform capillary action during injection of the underfill material.