Fuel leakage preventing structure and biofuel cell

A biofuel cell comprising:

• a battery cell unit including an electrode with an enzyme existing on a surface thereof;
• and
• a fuel leakage preventing structure configured to supply a fuel solution to the battery cell unit, wherein the fuel leakage preventing structure includes:
• a control valve;
• and
• a valve control unit configured to electrically control opening and/or closing of the control valve, wherein the valve control unit comprises:
• a first electrode formed on a first member, and
• a second electrode facing the first electrode formed on a second member,
• wherein the control valve is attached to at least one of a fuel supply inlet through which the fuel solution is introduced into the battery cell unit, and a fuel supply path connected to the fuel supply inlet, and the valve control unit opens and/or closes the control valve, depending on conduction between the first electrode and the second electrode caused by a pressing force applied on the first member.