An ultrasonic apparatus for promoting the blood flow in the head to thereby prevent a cerebral nervous disease such as dementia. An apparatus (1) for preventing a cerebral nervous disease provided with first oscillators (4a, 4b) generating sonic oscillation, wherein the blood flow in the brain is promoted by transmitting the oscillation generated by the first oscillators (4a,4b) via the scalp and the cranial bone to the vessels in the brain to thereby activate brain functions. The apparatus is also provided with modulators (17a, 17b) which relieve the rise and decay of the oscillation energy generated by the above-described first oscillators (4a, 4b). The brain can be gently massaged by the sonic oscillation generated by the first oscillators (4a, 4b). At the same time, the oscillation impact on the head can be softened by relieving the rise and decay of the oscillation energy with the modulators (17a, 17b).
