Provided is a biological signal measurement device capable of suppressing an influence of noise derived from a body motion of a test subject on a biological signal measurement result. The biological signal measurement device includes a placement portion on which a test subject is placed, one or more measurement sensors configured to measure a biological signal regarding the test subject, and a sensor holder configured to hold the measurement sensors. The placement portion has a recess. At least a part of the measurement sensor is arranged inside of the recess of the placement portion. The sensor holder and the measurement sensors are arranged to be physically separated from the placement portion without coming into contact with the placement portion.