To provide a downshift control device for an automatic transmission, and a downshift learning device for an automatic transmission, in which a speed change step of an automatic transmission can be downshifted to a speed change step desired by a driver by simple shift operation by the driver as the vehicle is traveling.

As an ECU for AT is set to position a shift lever of a shift unit at a shift position of an M-range, and when the shift lever is operated to the minus side (steps S11 and S12 are both determined positive), the speed change step that suits the travel state of the vehicle is read from a downshift learning map (step S13). The ECU for AT downshifts the speed change step of the automatic transmission by the number of speed change steps read from the downshift learning map (step S14). Then the ECU for AT changes the contents of the downshift learning map in accordance with the operation of the shift lever by the driver after the speed change step is read from the downshift learning map (step S15).