An upper has a front shell portion and a rear shell portion which includes a rear wall part, a front wall part, left and right wall parts that cooperate to confine a receiving space to receive the leg of the wearer. A leg support member is attached to an inner surface of the rear shell portion and extends from the rear wall part to the left and right wall parts. At least one of two end portions of the leg support member extends forwardly and outwardly from the rear shell portion and is manipulatable to tighten the leg support member around the wearer's leg so as to support and comfort the wearer's leg.