A wireless power transmission system comprising: a power transmission apparatus; a power reception apparatus; a load driving apparatus; and a power control apparatus that supplies power from a direct current power supply to the load driving apparatus through the power transmission apparatus and the power reception apparatus and outputs a load instruction value to the load driving apparatus, which load instruction value decides an operation condition of a load included in the load driving apparatus, wherein the power control apparatus includes the direct current power supply, a main control circuit that updates the load instruction value each time an operation load to be achieved by the load driving apparatus changes, and a communicator that outputs the updated load instruction value to the load driving apparatus, wherein the power transmission apparatus includes a power transmission inverter circuit that converts first direct current power supplied from the direct current power supply into first alternating current power, and a power transmission antenna that wirelessly transmits the converted first alternating current power, wherein the power reception apparatus includes a power reception antenna that is electromagnetically coupled with the power transmission antenna and receives the transmitted first alternating current power, and a rectifier that converts the received first alternating current power into second direct current power, wherein the load driving apparatus includes a load, a load inverter circuit that converts the second direct current power into second alternating current power, a load receiver that receives the load instruction value from the power control apparatus, and a load control circuit that determines a current of the second alternating current power on the basis of the load instruction value and drives the load, wherein the main control circuit updates, if the operation load to be achieved by the load driving apparatus changes, a control parameter for adjusting a voltage of the first alternating current power, the control parameter being used by the power transmission apparatus to convert the first direct current power into the first alternating current power, wherein the communicator outputs the updated control parameter to the power transmission apparatus and the updated load instruction value to the load driving apparatus, and wherein the power transmission apparatus further includes a power transmission control circuit that determines the voltage of the first alternating current power on the basis of the updated control parameter and that controls the power transmission inverter circuit using the voltage. a power transmission apparatus; a power reception apparatus; a load driving apparatus; and a power control apparatus that supplies power from a direct current power supply to the load driving apparatus through the power transmission apparatus and the power reception apparatus and outputs a load instruction value to the load driving apparatus, which load instruction value decides an operation condition of a load included in the load driving apparatus, wherein the power control apparatus includes the direct current power supply, a main control circuit that updates the load instruction value each time an operation load to be achieved by the load driving apparatus changes, and a communicator that outputs the updated load instruction value to the load driving apparatus, wherein the power transmission apparatus includes a power transmission inverter circuit that converts first direct current power supplied from the direct current power supply into first alternating current power, and a power transmission antenna that wirelessly transmits the converted first alternating current power, wherein the power reception apparatus includes a power reception antenna that is electromagnetically coupled with the power transmission antenna and receives the transmitted first alternating current power, and a rectifier that converts the received first alternating current power into second direct current power, wherein the load driving apparatus includes a load, a load inverter circuit that converts the second direct current power into second alternating current power, a load receiver that receives the load instruction value from the power control apparatus, and a load control circuit that determines a current of the second alternating current power on the basis of the load instruction value and drives the load, wherein the main control circuit updates, if the operation load to be achieved by the load driving apparatus changes, a control parameter for adjusting a voltage of the first alternating current power, the control parameter being used by the power transmission apparatus to convert the first direct current power into the first alternating current power, wherein the communicator outputs the updated control parameter to the power transmission apparatus and the updated load instruction value to the load driving apparatus, and wherein the power transmission apparatus further includes a power transmission control circuit that determines the voltage of the first alternating current power on the basis of the updated control parameter and that controls the power transmission inverter circuit using the voltage.