Abstract: An exhaust control valve assembly for a two-cycle engine is formed to effectively dissipate heat. The exhaust control valve includes a pair of valve elements disposed on opposite sides of a reinforcing wall. The reinforcing wall laterally bisects an opening of the exhaust port in a vertical direction. A valve stem is connected to bosses of the valve elements. The valve stem is supported in a rotatable manner by a pouch-shaped hole at one end and a through-hole at its other end. A drive system is coupled to an end part of the valve stem protruding outwards from the through-hole. The whole of the bosses of the valve elements is offset from the center of the reinforcing wall towards the through-hole. This arragnement allows heat, resulting from the exhaust gases passing by the valve elements, to be dissipate without overheating the valve stem on the pouch-shaped hole side.