To attain an efficient performance check by shortening the reproduction time for confirming a measured video in a biological light measurement, and to delete the data during a period including noise and a period without performing a task correctly in a short time.

The moving images of a subject in a first trial period (comprising a resting period when the subject rests and a task period in which the task is given to the subject) and a second trial period (comprising the resting period in which the subject rests and the task period in which the task is given to the subject) are picked up, and the moving image in the first trial period and the moving image in the second trial period are practically synchronized and displayed. Thus, the performance in each trial period is efficiently checked, and moving image reproduction time is shortened. Also, the data of the trial period including the noise and the trial period without performing the task correctly are deleted in a shorter time than heretofore.