Density fluctuations have been studied using the multichord interferometer over a wide range of plasma parameters in the ZT‐40M reversed‐field pinch experiment [Nucl. Fusion20, 1255 (1980)]. The total fluctuation power does not strongly depend upon the plasma current, and therefore, the relative fluctuation level decreases with increasing the current. Antisymmetric oscillations in the frequency region from 100–200 kHz are strongly excited in the outer region of the plasma column with increasing current. The maximum beta value attained seems to be inversely proportional to the magnitude of the fluctuations in this frequency region.