A medical treatment device includes a pair of holding members for opening and closing about an axis in accordance with an operation of an operating unit, and a shaft having one end connected to the operating unit and having the other end to axially support the holding members through the axis so as to allow the holding members to open and close. One of the holding members includes an energy application portion for contacting a body tissue to apply energy to the body tissue with the body tissue grasped by the holding members. The energy application portion is connected to a flexible substrate to be electrically connected to a lead wire provided inside the shaft extending from the other end of the shaft toward the one end of the shaft. The flexible substrate is connected to the lead wire closer to the one end of the shaft than the axis.
