The invention relates to a
circuit breaker for improving insulating property while being capable of reducing the
diameter of a
metal container of the
circuit breaker. The following components are arranged in the sealed container isolated by insulating
clapboard of central conductor and filled with insulting gas: a fixed side conductor installed on the central conductor of insulating
clapboard of one side; a fixed side
contact element connected with the fixed side conductor; an
electric arc contact terminal installed on the inner side of the fixed side
contact element; a fixed side shielding hood allocated to surround the fixed side
contact element; a movable element in contact with the fixed side contact element and the
electric arc contact terminal and firstly
cut off from the fixed side contact element before being turned off with the
electric arc contact terminal; a spring driving the electric arc contact terminal to move along the axial direction if the movable element is
cut off; and a following device of supporting framework; besides, a serially connected
inductor provided with coil part or
magnet is inserted between an electric arc extinguishing part of the electric arc contact terminal and the fixed side conductor.