Plasma polymerized Styrene thin films were used as a memory layer in a memory device. As for the memory layer, a ppS thin films were used for the organic memory device and their charge storage characteristic was investigated comparatively, where the charge storage effect was evaluated by a hysteresis voltage. The organic memory device with ppS thin film of 30nm and 50nm as memory layer showed promising memory characteristics such as hysteresis voltage of 20V and 28V. The ppS revealed promising charge storage properties which confirms that an organic memory device without floating gate could be successfully implemented by using the ppS thin film as a memory layer.