PURPOSE: To make it possible to prevent the adhesion of sea-organisms to the structure of a sea water channel by applying a very narrow high voltage pulse several times repeatedly to the sea water passing through the entrance portion or the inner portion of the structure of the sea water channel.

CONSTITUTION: Larvae of adhesive sea-organisms in the sea water flowing in from the sea water intake 1 are applied with a very narrow high voltage pulse several times repeatedly when passing through a device 5 for applying a very narrow high voltage pulse, and they are kept in paralysis continually or killed and eliminated. Therefore the adhesion and the growth of the larvae to and on the wall of the water intake 2 or the intake side tube channel 4 can be prevented. Under the application of the very narrow high voltage pulse of only one time, the larvae are once paralyzed but recover the activity with time, but by applying the said pulse several times repeatedly the larvae are kept in paralysis continually or killed.