To provide an ultrasonic automatic reaction apparatus in which a reaction is advanced automatically, the constitution of which is simplified, the operation of which is facilitated and from which a correct detected result can be obtained.

This ultrasonic automatic reaction apparatus 1 is composed of a control portion 10 which is arranged in the upper part of this reaction apparatus 1 and provided with timers 11, 12, 13 and a counter 14 for controlling the oscillation of an ultrasonic wave and a reaction portion 20 which is arranged in the lower part of this reaction apparatus 1 and provided with a treatment tank 21 and an ultrasonic oscillation unit 26. After the work of oscillating the ultrasonic wave by using the ultrasonic oscillation unit 26 for a fixed time and then stopping the oscillation for a fixed time is repeated by a predetermined number of times by using the timers 11, 12, 13 and the counter 14 of the control portion 10, the oscillation is stopped for a fixed time. A series of the above repeating work is repeated continuously for a fixed time.