A biosensor for electrochemically measuring a sample may include a first member made of an insulating material, an electrode system including a working electrode and a counter electrode formed on the first member, a second member fixed over the first member, a sample flow channel provided between the first member and the second member, a hydrophilic section provided on at least a part of the internal surface of the sample flow channel and extending from a first end near the electrode system to a second end on the opposite side, and a flow stop area provided on a section adjacent to the second end on the first member or on the internal surface of the sample flow channel.