The purpose of the present invention is to provide a nanoparticle dispersion liquid of an α-galactosylceramide-related compound that can be administered in the form of a stable dispersion liquid using water as a solvent. According to the present invention, it is possible to obtain a nanoparticle dispersion liquid, which is not in the form of a liposome dispersion liquid obtained by using a phospholipid or the like, and also to control the size of nanoparticles.
