PROBLEM TO BE SOLVED: To provide a growth accelerating apparatus for plant and a growth accelerating method using the same which surely perform the growth acceleration of plant by the electric field effect paying attention to the biological effect of asymmetric AC electric field.SOLUTION: The apparatus and the method adopt the following technical means. An high voltage AC output circuit is provided with a positive bleeder circuit in which a diode and a resistance are combined, and in the circuit elements, an asymmetrical AC high voltage power supply is capable of obtaining an asymmetrical AC high voltage whose crest value ratio of positive voltage to negative voltage is 1:X(&ne；1) by selecting a resistance value of the resistance. The asymmetrical AC high voltage power supply is provided with a pair of parallel plate-like electrodes 1 and 1. These electrodes 1 and 1 are supported by a support 11 formed of an insulator, a plant 2 where the plant P is placed is disposed between the electrodes 1 and 1, and the asymmetric AC electric field is uniformly applied to the plant P on the surface of the plant 2.
