A channel, comprising: a first sidewall that extends along one of an inner surface of a door glass and an outer surface of the door glass in a cross section orthogonal to a longitudinal direction of the channel, and includes a first end portion, a second end portion, and a first locking portion, the second end portion being located on a side opposite to the first end portion, and the first locking portion being located between the first end portion and the second end portion to lock a glass run that guides the door glass; a second sidewall that extends along the other of the inner surface and the outer surface of the door glass in the cross section orthogonal to the longitudinal direction of the channel, and includes a third end portion, a fourth end portion, a second locking portion, and a fixing portion, the fourth end portion being located on a side opposite to the third end portion, the second locking portion being located between the third end portion and the fourth end portion to lock the glass run, and the fixing portion being located between the fourth end portion and the second locking portion and configured to be fixed to a door constituting member constituting at least a part of a door; and an end wall that is connected to the first end portion and the third end portion and extends along an end surface of the door glass, wherein the second sidewall has an inner surface that faces the first sidewall and an outer surface that is located on a side opposite to the inner surface, the outer surface being configured to be in contact with the door constituting member, characterized in that The fixing portion extends in a direction obliquely intersecting the first sidewall to be located farther away from the first sidewall as the fixing portion is located farther away from the end wall, and the first sidewall is provided with an opening that includes a hole or a notch and exposes the fixing portion in a direction normal to the inner surface of the second sidewall. a first sidewall that extends along one of an inner surface of a door glass and an outer surface of the door glass in a cross section orthogonal to a longitudinal direction of the channel, and includes a first end portion, a second end portion, and a first locking portion, the second end portion being located on a side opposite to the first end portion, and the first locking portion being located between the first end portion and the second end portion to lock a glass run that guides the door glass; a second sidewall that extends along the other of the inner surface and the outer surface of the door glass in the cross section orthogonal to the longitudinal direction of the channel, and includes a third end portion, a fourth end portion, a second locking portion, and a fixing portion, the fourth end portion being located on a side opposite to the third end portion, the second locking portion being located between the third end portion and the fourth end portion to lock the glass run, and the fixing portion being located between the fourth end portion and the second locking portion and configured to be fixed to a door constituting member constituting at least a part of a door; and an end wall that is connected to the first end portion and the third end portion and extends along an end surface of the door glass, wherein the second sidewall has an inner surface that faces the first sidewall and an outer surface that is located on a side opposite to the inner surface, the outer surface being configured to be in contact with the door constituting member, characterized in that The fixing portion extends in a direction obliquely intersecting the first sidewall to be located farther away from the first sidewall as the fixing portion is located farther away from the end wall, and the first sidewall is provided with an opening that includes a hole or a notch and exposes the fixing portion in a direction normal to the inner surface of the second sidewall.