A multi-stage transmission for vehicle may include an input shaft; and an output shafts; first to fourth planetary gear devices transmitting rotary force between the input and output shafts, each of them having three rotary elements; and at least six shifting elements connected to the rotary elements of the planetary gear devices; wherein first rotary element of the first planetary gear device is permanently connected to the input shaft and second rotary element of the third planetary gear device, second rotary element is installed to be fixable by any one of the shifting elements and variably connected to first rotary element of the third planetary gear device and first rotary element of the fourth planetary gear device, and third rotary element is variably connected to first rotary element of the second planetary gear device and permanently connected to second rotary element of the second planetary gear device.