A multi-stage automatic transmission using a reduction planetary gear and a planetary gear set in which the respective thrust forces generated thereat are supported by a low bearing load or a low case load. The automatic transmission is provided with a reduction planetary gear, coupled to an input shaft to fix a reaction force element so as to output a reduction rotation to an output element, and a planetary gear set, that outputs a speed shift rotation upon input of the subsequent reduction rotation. During at least first gear driving, there is provided a force transmission route in which thrust forces generated at one element of the reduction planetary gear and one element of the planetary gear set, respectively, are transmitted. In that route, a torsion direction of the spiral teeth of the respective elements are set such that a direction of a thrust force of the element and a direction of the thrust force of the other element are different from each other during first gear driving.