In the related art, various techniques for holding the degree of opening of an opening and closing body of a vehicle at an arbitrary position are proposed. For example, JP 61-191781A (Reference 1) discloses a technique in which a sensor for detecting the presence or absence of contact of a human body with a door of an automobile is provided and when the human body is in contact with the door, holding of the door is released and when the human body is not in contact with the door, the door is held. Such an opening degree holding mechanism is provided, whereby at the time of the opening and shutting of the door, it is possible to automatically hold the door at an arbitrary degree of opening which an occupant wants.
However, it cannot be said that a method of controlling a holding force of a door based on only a sensor for detecting the presence or absence of contact of a human body necessarily provides good operability. For example, if the human body is separated from the door, a door holding mode is entered, and thus a brake is applied, and therefore, it is not possible to perform opening and shutting of the door with inertia by giving momentum to the door. That is, if the body does not touch an operating portion of the door, the door cannot be moved, and therefore, an impression that operability is poor relative to a normal door without an opening degree holding mechanism is sometimes given to a user.