A power-consumption-amount estimation apparatus estimating a power consumption amount of an industrial machine including a motor, a machine driven by the motor, and an amplifier driving the motor, includes: an operation-pattern-information obtaining unit; a dynamics-information obtaining unit; a circuit-information obtaining unit obtaining amplifier information and motor information; and a power-consumption-amount calculation unit executing a process of calculating power of each of the motor and the regenerative resistor based on operation-pattern information, dynamics information, amplifier information, motor information, and a bus voltage simulated value and calculating power of the industrial machine based on the calculated power and execute a process of updating the bus voltage based on the calculated power of each of the motor and the regenerative resistor and the calculated power of the industrial machine, over a specified period, and calculating a power consumption amount of the industrial machine by integrating the calculated power of the industrial machine.