PROBLEM TO BE SOLVED: To provide a technique for suppressing increase of size of a device to perform growth promotion of vegetables and mushrooms.SOLUTION: There is provided a growth promotion device to promote growth of a culture object comprising a vegetable or a mushroom, and provided with a coil, a storage vessel for storing the culture object and placed on an axle line of the coil, and an AC power unit to pass AC current of a single frequency between 300 Hz and 100 kHz through the coil.