A parking mechanism of a transmission includes a parking sprocket plug having a pawl portion to be engaged with a parking gear, a parking rod which has a bulge portion and causes the parking sprocket plug to operate, and a bracket which has a rod support member supporting the parking rod. The parking sprocket plug also has a support piece. When the bulge portion is disengaged from a projection, the support piece is hooked on the bulge portion, and the parking sprocket plug is supported in a position where the pawl portion is disengaged from the parking gear. Thereby, a parking mechanism which incurs no malfunction and requires small force for operation is provided.