A planetary gear set for an automatic transmission of a vehicle includes a central shaft having a main lubrication path and a penetration hole connected with the main lubrication path, a sun gear, a pinion gear, a ring gear, a planet carrier, a first bearing disposed between a side of the sun gear and the planet carrier, a second bearing disposed between the planet carrier and the pinion gear, a clutch hub shaft, a sun gear lubrication path that connects the main lubrication path to the first bearing through the penetration hole, a pinion gear lubrication path that connects the main lubrication path to the second bearing through the penetration hole, and a sealing element disposed in a passageway connecting the pinion gear lubrication path and the sun gear lubrication path so as to close the passageway.