Recent augmented reality systems can provide information on planes that are different from real environment. Therefore, we examined whether information presented on different depth planes affect visual attention to contribute to the realization of secure augmented reality systems. Experimental results using the object substitution masking, i.e., OSM, paradigm demonstrated that the visibility of targets was affected by the relative depth between the target and the mask. These results suggested that the visibility of information provided not only on a single plane but also on different depth planes by the current augmented reality systems could be reduced.