In a system for performing imaging measurement of a test object by mounting many optical fibers to the test object, incident positions of the test object on which to illuminate light, detection positions of the test object from which to detect light and measurement positions which are determined from a positional relationship between the incident positions and the detection positions are displayed as graphic elements on a display unit. A state of detection signal level or a change in the state is displayed as a change in color or in pattern of the graphic element. Further, incident optical fibers for illuminating light to the test object and detection optical fibers for detecting light from the test object are mounted to the test object, and light emitting elements are mounted to probes to be mounted to the test object and interlocked with the change of the graphic elements.