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