The present invention provides a percutaneously absorptive preparation for preventing or treating allergic eye disease, which comprises olopatadine or a salt thereof as an active ingredient. In addition, the present invention provides a method for preventing or treating allergic eye disease, which comprises applying a percutaneously absorptive preparation comprising olopatadine or a salt thereof to the skin surface including the skin surface of an eyelid, thereby casing transfer of a therapeutically effective amount of olopatadine or a salt thereof from the preparation to an anterior ocular segment through the skin of the eyelid rather than a systemic blood flow. The present preparation can exert a pharmacological effect over a prolonged period by a single application, as compared to conventional preparations such as eye drops.