PURPOSE: To improve texture, taste and fragrance of spherical marine alga food having good palatability and sufficiently making the most of flavor of marine alga by dispersing a pulverized marine alga into calcium alginate gelatinized in a spherical state.

CONSTITUTION: A marine alga treated with a cell wall hydrolyzing enzyme (e.g. cellulose hydrogenating enzyme) is heated to 60-80°C, enzymatic action is deactivated or a frozen marine alga is ground and mixed with water to give a paste-like material containing the marine alga pulverized into ≥60 meshes particles size. The paste-like material is mixed with 0.7-1.6% solution of alginate (e.g. sodium alginate) to give a mixed solution having 250-150cp viscosity, which is dripped into 0.5-2% aqueous solution of Ca salt (e.g. calcium lactate) and gelatinized into a spherical state to give a spherical marine alga food having a pulverized marine alga dispersed into calcium alginate gelatinized in a spherical state.