Problem: To provide a discharge valve apparatus able to be disposed on a flush toilet with a relatively low silhouette by shortening the length of the valve body main shaft and lowering the height of the discharge valve apparatus.Solution Means: A discharge valve apparatus having: a small-flush float mechanism and a large-flush float mechanism; wherein the valve body main shaft includes a single shared projecting portion which locks to the large-flush cam lock portion when the required amount of pull-up for the large-flush mode has been pulled up, and locks to the small-flush cam lock portion when the amount of pull-up required for the small-flush mode has been pulled up.