An oil supply device for an electric vehicle powertrain apparatus, includes an electric oil pump, a motor lubrication flow path connected to the electric oil pump and provided to supply oil from the electric oil pump to a bearing of a motor, a motor cooling flow path branched from the motor lubrication flow path to supply oil for cooling the motor from the electric oil pump, and a cooling control valve apparatus provided in the motor cooling flow path to control oil supplied to the motor through the motor cooling flow path according to an operating state of the electric oil pump.