To prevent a user from getting wet with rain when getting on/off an automobile or the like during folding/unfolding an umbrella in a rainy day.

A rainproof sheet for automobile door comprises: an opening for a telescopic sheet; an enhanced strong magnet; an automatic telescopic device including a flat spiral spring and the like; and a rainproof sheet capable of getting spread (extended) toward the door. A magnet for fixing sheet on the door side is more slender than that of on the automobile body side. A sheet winding-up core is a rod formed in a cone shape such that its door hinge side is smaller than its outer side. When opening the door, the user is protected from rain by a spread (extension) of the rainproof sheet over a space generated between the automobile body and the automobile door.