PURPOSE: To promote growth of laver and to contrive to increase yield of laver, by attaching proteolysis essence obtained by hydrolyzing protein with protease to laver at a proper time in a culture process and cultivating the laver in seawater.

CONSTITUTION: Proteolysis essence obtained by hydrolyzing protein with protease is attached to laver in a proper time in culture process of seeding period, germinating period, seedling raising period and culture period, the laver is cultivated in seawater, growth of laver is promoted and growth is intensified. Essence of fish and shellfish or essence of edible animal obtained by hydrolyzing a fish and shellfish or an edible animal with protease is usable as the proteolysis essence. Attachment of the proteolysis essence to laver in culture is carried out by scattering or coating of the proteolysis essence or by immersion in the proteolysis essence.