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