To provide an activator of gene expression of molecular chaperone gene and applications thereof.This activator of gene expression of molecular chaperone gene contains an eggshell membrane component, for example, a powder containing eggshell membrane or a soluble eggshell membrane component. Moreover, the powder containing eggshell membrane used in the present invention may be a fine powder preferably having 6 μm or less in the mean volume particle diameter of the fine powder containing eggshell membranes, and/or 20 μm or less in the maximum volume particle diameter thereof, but not limited to these values.