Abstract: A simple sound intensity meter has been constructed. The errors associated with measurement are in fair agreement with the results obtained from theory. The results of measurement are affected apparently by the relative phase shift between the two microphones of the transducer of the sound intensity meter, especially in the lower frequency range. In terms of the method of direction-inverted average, the errors have been reduced. Through the analogous experiment in the anechoic chamber and in the reverberant room, it. is indicated that the sound power can be determined effectively in situ by the measurement of sound intensity.