Shift control apparatus and transmission apparatus

A shift control apparatus controlling a stepped transmission that is mounted in a vehicle and changes a shift speed by switching an engagement state of a friction engagement element by driving a hydraulic actuator, the shift control apparatus comprising:

• a gear ratio setting unit that sets a gear ratio to change gradually with respect to a change in a traveling state;
• a shift speed change determining unit that determines a change of shift speed by comparing the set gear ratio with a reference gear ratio corresponding to each shift speed;
• a shift speed change predicting unit that predicts in advance a change of shift speed by the shift speed change determining unit based on the set gear ratio, a rate of change in the set gear ratio, and an engagement preparation time which is a time needed for engagement preparation of the friction engagement element;
• and
• a shift control unit that controls the hydraulic actuator so that engagement preparation of a friction engagement element to be engaged is performed when a change of shift speed is predicted by the shift speed change predicting unit and performs standby, and controls the hydraulic actuator so that a hydraulic pressure needed for engaging the friction engagement element is supplied to a hydraulic servo of the friction engagement element when a change of shift speed is determined by the shift speed change determining unit.