Biosignal-measuring instrument

A bio-signal measuring instrument is provided to measure the bio-signal accurately and conveniently regardless of body condition of the user by measuring the bio-signal of the user from a radial artery. A bracelet membrane(110) is worn around the wrist of a user. A fixing support part(120) is installed in a first side of the bracelet membrane and supports the first side of the wrist. A movement support part(130) is installed in a second side of the bracelet membrane, and adheres to the second side of the wrist as moving toward the fixing support part. An information control unit(140) calculates distance between the first side and the second side of the wrist by sensing the movement distance of the movement supporting part, and calculates displacement of radial artery of the wrist by using the distance between the first side and the second side of the wrist and a predetermined constant.