An ameliorating agent for chronic obstructive pulmonary disease (COPD) containing as an active ingredient a lecithinized superoxide dismutase represented by the following general formula (I):SOD′(Q−B)m (I)(in the formula SOD′ represents a residue of the superoxide dismutase； Q represents a chemical crosslinking； B represents a residue without a hydrogen atom of a hydroxyl group of lysolecithin having the hydroxyl group at the 2-position of glycerol； m is the average number of bonds of lysolecithin to one molecule of superoxide dismutase and represents an integer of 1 or more). The ameliorating agent for COPD is intravenously administered or inhalation-administrated.
