A separation unit is a configuration that is arranged vertically, and thus bubbles generating from the electrode will not negatively influence the contact location between the transfer membrane and separation unit. An anode (32) is arranged at a position separated by a certain distance in the conveying direction (X) of the transfer membrane (1) from the dispensing part (50a) of an electrophoresis gel chip (50). An insulating electrode cover (35) for setting free bubbles generating from the anode (32) is arranged at an upper part of the anode (32).