PURPOSE: To reduce the cost with use of a comparatively simple circuit constitution and at the same time to easily obtain an output waveform which is extremely approximate to a sine wave.

CONSTITUTION: In regard to a sine wave generating method and a sine wave generating circuit, a rectangular wave is inputted to a cube circuit 1 which generates a cubic output waveform in response to an input rectangular wave. Then the cubic current emerging at the output side of the circuit 1 and a waveform obtained by inverting the phase of the input triangular wave are added to a differential current. Then the current/voltage conversion is carried out with the common output load resistance. Thus a sine wave is obtained.