To provide a control device of automatic transmission for vehicle which can determine a gear condition of automatic transmission with sufficient accuracy in a gear control of the automatic transmission for vehicle.

The gear condition of automatic transmission 12 can be determined with sufficient accuracy in such a way that the gear condition of the automatic transmission 12 is determined based on an accumulated pulse number Nipc, obtained from a rotation of an input shaft 26 when an output rotating member 28 is rotated in integer, and predetermined reference pulse number Nipcest. Concretely, the accumulated pulse number, being an index of the input shaft 26 which is counted when the output rotating member 28 rotates in integer, is known to be set as a predetermined reference pulse number based on the gear condition. Accordingly, the gear condition of the automatic transmission 12 can be determined by comparing the accumulated pulse number Nipc of the input shaft 26 which is counted actually with the reference pulse number Nipcest.