[en] The trajectory of charge particles will be changed by electrostatic wave with a large amplitude in plasma. The dispersion relation of drift waves is derived with the help of integration along the changed trajectory. It shows that the drift wave instability can be suppressed by a so-called 'quasi-Larmor radius effect' as long as the condition, K·S_e>K·S_i, is satisfied, where K is the wave number of drift wave, S_e,S_i, caused by electrostatic waves, are the amplitudes of shift of charge particles, respectively. (author) 4 refs