The present invention provides a hair regrowth promoter comprising an egg-yolk protein hydrolysate as an active ingredient. The egg-yolk protein hydrolysate is a safe ingredient produced from a natural source, and therefore can be widely used in daily consumable products, such as food and drink products, medicaments, animal feeds, and dietary supplements, or as a food additive, etc. The promoter etc. of the present invention can be orally administered and is thus very advantageous.