Provided is a novel nanoparticle, a contrast agent for magnetic resonance imaging containing the same, and a ligand compound used for the production of the nanoparticle. The present invention relates to a nanoparticle including: a metal particle containing ferric oxide； and a ligand represented by formula (3), where the ligand is bonded to a metal atom on the surface of the metal particle. (In the formula, m is an integer of 1 to 4, and the broken line represents a coordinate bond with a metal atom on the metal particle surface.)
