A multi stage transmission for a vehicle may include an input shaft and an output shaft; first to third planetary gear device provided to transfer a torque between the input shaft and the output shaft and each including three rotating elements; and at least six shifting elements connected to the rotating elements of the first to third planetary gear devices, wherein the first planetary gear device has a first rotating element continuously connected to the input shaft and variably connected to a third rotating element of the third planetary gear device, a second rotating element fixedly installed by any one of the shifting elements and variably connected to the third rotating element of the third planetary gear device, and a third rotating element variably connected to a first rotating element of the second planetary gear device and continuously connected to a first rotating element of the third planetary gear device.