Name : Shigeru YOSHIDA Institute : ICRR E-mail : syoshida@icrr.u-tokyo.ac.jp TITLE : A search for horizontal air showers induced by extremely high energy energy cosmic neutrinos observed by Akeno Giant Air Shower Array ABSTRACT : We have made a systematic search for air shower events induced possibly by Extremely High Energy (EHE) cosmic neutrinos detected by the Akeno Giant Air Shower Array (AGASA). The lateral distribution of secondary shower particle densities and their shower front curvature are found to be closely related to atmospheric depth of the shower maximum which makes it possible to discriminate anomaly penetrating air shower events from the regular hadron induced air showers. We have found no significant enhancement on intensity for deeply penetrating air showers. The experimental upper bound of EHE neutrino fluxes by the AGASA detector is obtained to be presented..