A method of producing crystal of a poorly water-soluble pharmaceutical compound, including mixing a solution of a poorly water-soluble pharmaceutical compound in a good solvent and nanobubble water or an aqueous nanobubble solution to precipitate crystal of the poorly water-soluble pharmaceutical compound. The crystal of a poorly water-soluble pharmaceutical compound obtained by the method is microparticulate and has more uniform particle size distribution, and is superior in the absorbability and sustainability.
