PURPOSE: To perform an unmonotonous therapy and to obtain more refreshing feeling by providing a plurality of therapeutic modes preprogramed by means of a CPU with a built-in timer, using a rectangular wave as a standard for each therapeutic mode and changing automatically an output condition by means of a pulse width and a polar conversion in a determined time.

CONSTITUTION: A low frequency therapeutic instrument is totally controlled by means of a CPU 2 with a built-in timer 1. Two ceramic oscillators 3a and 3a are built in the CPU 2 and a rock crystal 3c connected in series with capacitors 3b and 3b is connected with the ceramic oscillators 3a and 3a to constitute an oscillator circuit 3. The CPU 2 controls a booster circuit 14 using an output circuit 13 according to a preset program of each therapeutic mode and outputs therapeutic pulses to output terminals 16 and 16 through an output adjusting circuit 15. A standard output wave shape of the low frequency therapeutic instrument is a rectangular pulse with the max. wave height of 130V and the output condition such as a repeating frequency, a pulse width and plurality are automatically changed.