A separable ball valve apparatus and ball valve assembly capable of selectively opening / closing a separable flow path are provided. The separable ball valve apparatus comprises a separable pipe member having a flow path through which fluid flows, a ball member having at least two balls disposed in the pipe member, opening and closing the flow path, and adjacent to each other, and an opening / closing member configured to control the ball member to open / close the flow path, wherein the balls have through-holes, respectively, and the opening / closing member includes a gear train configured to control the opening / closing of the at least two balls. Therefore, it is possible to simply open / close pipes having the flow path and detachably attach the pipes, increase space utilization due to removal of a separate coupling space for attachment / detachment of the pipes, and simultaneously open / close the two pipes, which are separated from each other through one operation.