A control apparatus for an automatic transmission that selectively engages a plurality of frictional engaging elements for shift control includes a shift instruction device, a temperature calculator, an engageability determiner, an engagement delay device, a load calculator, a cumulative load calculator, and a threshold temperature changer. The engageability determiner is configured to determine whether at least one of the plurality of frictional engaging elements is engageable or not based on a comparison between a temperature of the at least one of the plurality of frictional engaging elements calculated by the temperature calculator and a predetermined threshold temperature in a case where the shift instruction device outputs a shift instruction. The threshold temperature changer is configured to change the predetermined threshold temperature in a case where a cumulative load calculated by the cumulative load calculator reaches a value greater than or equal to a predetermined value.