A low frequency fast wave current drive scenario for ITER (f ~ 17 MHz < fcT, where fcT is the cyclotron frequency of tritium ions) has been analysed using a 1-D full wave code (TASK/W1). The current drive efficiency varies significantly with changes in the electron density owing to effects of the cavity resonance, even for the standard value of the peak of the parallel wave number N|| chosen for ITER (peak of a main lobe, N||(p)=2.3). The peak value of the current drive efficiency, according to the cavity resonance, agrees with that for the single wave mode for a large number of antennas in the toroidal direction. The antenna loading resistance as well as the current drive efficiency reach a maximum value nearly at the cavity resonance corresponding to that of the eigenmode. Therefore, it may be possible to optimize the current drive efficiency by optimizing the antenna coupling resistance to its maximum value. Frequency feedback control with a combination of instantaneous bandwidths and several preset frequencies is considered to achieve and to maintain good current drive efficiency against a possible change of the electron density. It is shown that this scheme allows good current drive efficiency (γ ~ 0.5 × 1020 A.W-1.m-2 with N||(p)=1.5), similar to that for neutral beam current drive