A surgical instrument includes: a clamp section main body which is movable between a close position that is close to a vibration transmission member and an away position that is away from the vibration transmission member； a pressure pad provided on the clamp section main body and provided on a position that is close to the vibration transmission member, the pressure pad being brought into contact with the vibration transmission member when the clamp section main body is in the close position； and a pressing member which is configured to press the vibration transmission member in association with the clamp section main body coming close to the close position, and is configured to decrease pressure of contact between the pressure pad and the vibration transmission member.
