To reduce the labor of workers as much as possible when an antiaircraft beacon is installed at a place hard to access.

In the method for installing an antiaircraft beacon in tomographical survey using an air photo, an antiaircraft beacon is formed, at first, of a biodegradation synthetic resin and then a point becoming photographic coordinate is obtained by survey. The antiaircraft beacon is installed in the photographic coordinate thus obtained such that it can touch microorganisms performing biodegradation.