PROBLEM TO BE SOLVED: To provide a can for ocean-greening which stably and favorably supplies a ferrous iron in water, promote growth of a marine plant, and achieve the ocean-greening. SOLUTION: The can for ocean-greening includes: a body part accommodating a mixture of iron powder consisting of metallic iron, iron oxide, and inevitable impurities, and an organic acid; and a lid part sealing the body part and openably provided. COPYRIGHT: (C)2012,JPO&INPIT