A biological information measurement system includes a dewar, a single imaging device, and a hardware processor. The dewar covers a head of a subject and contains sensors that are arranged for detecting biological signals. The single imaging device acquires an image in which three or more reference points and the dewar are captured, the reference points being set in relation to the subject. The hardware processor is configured to: measure brain neural activity of the subject based on the biological signals detected by the sensors； determine positional relationships between the reference points of the subject and the sensors based on the reference points and positional relationship data of the dewar； and re-determine the positional relationships between the reference point of the subject and the sensors, based on images that are acquired by the single imaging device at different times.
