To provide a brain wave induction device which achieves the accurate induction of brain waves in a shorter time and enables the outputting of ultralow-frequency sounds optimal for the brain wave induction despite the required adjustment of the sound pressure level of audible sounds, for example, when the audible sounds are overlapped on the ultralow-frequency sounds outputted to human beings.

The brain wave induction device has an ultralow-frequency signal generation part 3 which gets an electric signal inputted into an output part 5. The electric signal outputted by the ultralow-frequency signal generation part has a frequency within an range of 7-12 (Hz) outputted from the output part while corresponding to a sound wave with its sound pressure level within a range of 60-95 (dB).