A medical instrument includes a housing, a movable handle, and a spring. The movable handle is configured to move between a first position as an opened position and a second position as a closed position with respect to the housing. The spring is provided between the housing and the movable handle. The spring is configured to apply a biasing force to the housing or the movable handle. The spring is provided to alleviate an increase in the biasing force generated in the spring in response to the movable handle moving from the first position to the second position.