In our former report, we have proposed a resonant-electrode-type optoelectronic oscillator (RE-OEO). An optical modulator used In the RE-OEO has a resonant electrode, over which standing wave arises around the frequency of the resonance. The frequency components out of the resonant frequency are highly suppressed, so that single-mode oscillation in microwave frequency is easily achieved. In addition, the RE-OEO oscillates with lower input threshold power since modulation efficiency can be improved at the resonant condition. We experimentally investigate, in this paper, the characteristics of injection locking for the RE-OEO when microwave near the oscillation frequency is launched on it.