Authors have proposed a printed rectangular monopole antenna for circular polarization. The radiation characteristics of the wideband circular polarization are achieved by designing the antenna asymmetrically. The simulated bandwidths (3dB-axial ratio with 10dB-return loss) are approximately 64%. In this paper, miniaturization of the antenna proposed by authors is examined. The size of the antenna miniaturized in this paper is approximately 40% of the antenna proposed in the authors' previous study. The bandwidth is approximately 40%.