A medical apparatus includes a first clamp portion; a pivot shaft; a second clamp portion rotatable around the pivot shaft, and movable between an opened position in which the second clamp portion is distant from the first clamp portion, and a closed position in which the second clamp portion is adjacent to the first clamp portion; and an electrode member provided on the second clamp portion, and opposed to the first clamp portion, the electrode member forming a clearance in cooperation with the first clamp portion in the closed position, the clearance in a second position distant from the pivot shaft being smaller than the clearance in a first position adjacent to the pivot shaft, to adjust holding pressure.