Provided is a skeletal muscle regeneration promoter for a muscular disorder or myopathy comprising a chondroitinase as an active component, which skeletal muscle regeneration promoter enhances, when administered into a muscular fiber of a mammal with the muscular disorder or myopathy, the regeneration of such a muscular fiber. The above-mentioned chondroitinase degrades chondroitin sulfate that is present at the outer perimeter of the above-mentioned muscular fiber and thereby inhibition of the regeneration of the muscular fiber by the above-mentioned chondroitin sulfate disappears, which makes it possible to enhance the regeneration and enlargement of such a muscular fiber.
