Disclosed is an apparatus for measuring biological information and an earphone having the same for contacting with a uniform pressure a user body part using an elastic member. The apparatus includes a first housing; a second housing foldably connected with the first housing; a third housing foldably connected with the second housing and provided with a sensor for measuring the biological information; a plurality of joint parts for connecting the housings to be folded or unfolded to each other; one or more locking parts for restraining or releasing the housings to be folded or unfolded to each other; and the elastic member for applying the same pressure to make the sensor contact with the user's body by enabling the respective housings to be folded or unfolded using a stress-strain.