Protein crystallization apparatus and protein crystallization method

A protein crystallization apparatus is comprised of a vessel supporting section and a rotating unit. A vessel is detachably fixed to the vessel supporting section. The rotating unit rotates the vessel supporting section around first and second rotation axes. The vessel is comprised of a vessel section having an opening; a sealing section which seals said opening of said vessel section; an absorption member which is provided in the vessel section and in which precipitant solution is absorbed; and a button provided apart from the absorption member to hold protein solution. Precipitant evaporates and diffuses in an inside of the vessel section while the vessel supporting section is rotated. The precipitant is absorbed by the protein solution and a protein crystal is precipitated.