TRANSMISSION CONTROL DEVICE AND TRANSMISSION CONTROL METHOD

A transmission control device () includes: a gear ratio calculating unit () for calculating a target gear ratio of a transmission () based on a gear ratio control mode, to thereby control the transmission; an electric motor drive torque calculating unit () for calculating a drive torque of an electric motor () based on the gear ratio control mode when drive of the electric motor () is permitted; and an engine torque calculating unit () for calculating an output torque of an engine () based on the gear ratio control mode so as to achieve a best fuel efficiency operation state. The gear ratio calculating unit () switches processing of calculating a gear ratio based on whether or not the drive of the electric motor () is permitted.