Polyacrylonitrile nanofibers containing a series of porphyrin molecules were prepared by an electrospinning method. We first succeeded in controlling the position of porphyrin molecules in the nanofibers by considering porphyrin characteristics and the electrospinning conditions. It was concluded that positive charge of cationic porphyrin, TMPyP, and higher applied voltages were effective to locate the porphyrin molecules on the polymer nanofiber surfaces because of the electrostatic repulsion among the molecules during the electrospinning process. The polymer nanofibers with cationic manganese porphyrin (Mn-TMPyP) on their surface repeatedly showed superoxide dismutase (SOD) activity, which is a catalytic activity to work as antioxidant in various biochemical fields. The positional control of functional molecules in nanofibers demonstrated a new possibility of nanofiber applications.