The present invention relates to a magnetic resonance imaging (MRI) contrast agent coated with carboxylated mannan, particularly a carboxylated mannan coated superparamagnetic MRI contrast agent specifically targeting antigen presenting cells and having excellent in vivo stability, and a method for producing the same. The MRI contrast agent coated with carboxylated mannan of the present invention can provide excellent in vivo stability and biocompatibility owing to its high surface negative charge, and can be introduced specifically into antigen presenting cells owing to mannose of mannan, so as to visualize the antigen presenting cells and the tissue containing the antigen presenting cells in MRI.