A trocar including a distal-end tube portion that is disposed inside the body and has a first inner hole through which a medical device can be inserted; a proximal-end tube portion that is disposed outside the body and is connected to the distal-end tube portion, the proximal-end tube portion having a second inner hole that communicates with the first inner hole and has an axis which can be disposed in a direction not parallel to an axis of the first inner hole; and a movement facilitating portion that is disposed on at least one of the inner surface of the first inner hole and the inner surface of the second inner hole to facilitate the movement of the medical device inside the inner hole.