To perform shift control suitable for a tractive traveling state and to suppress rising of a rotational frequency of a power source to a prescribed rotational frequency or higher.

This shift controller for an automatic transmission is capable of selectively switching a plurality of shift control modes with different shift control contents for controlling gear ratios of the automatic transmission provided in an output side of the power source. It is provided with a shift control mode selecting means (step S1 to step S3) for selecting a first shift control mode, when an output control demand to the power source is in a predetermined state, and a shift control mode switching means (step S4 to step S8) for switching from the first shift control mode to a second shift control mode, when the first shift control aspect is selected and a physical value related to the rotational frequency of the power source shows a particular change.