A transmission gear shifting control system is selective of gear ratio of an automotive automatic power transmission. The control system employes a strategy of learning of driving condition in order to select one of a plurality of vehicle driving pattern so as to adapt to the vehicular driving condition and the driver's desire, by means of neuron computer. The system monitors a plurality of vehicle driving parameters and storing driving pattern data in an associative storage for forming stored driving pattern. The driving pattern data is stored in terms of relevant one of transmission gear shifting patterns so that the transmission gear shifting pattern can be selected in response to entry of the stored relevant driving pattern. The control system is further operable for associatively recollecting one of driving pattern on the basis of the monitored driving parameters and stored driving patterns.