A method of producing a metal complex-supporting mesoporous material that can support a metal complex in the pores thereof without causing aggregation of the metal complex. A metal complex-supporting mesoporous material supporting a metal complex in the pores thereof without causing aggregation of the metal complex. A method of producing a mesoporous material supporting metal-containing nanoparticles using the metal complex supported in the pores of the mesoporous material as a template. A solution of a metal complex prepared by a phenyl azomethine dendrimer compound having a specific structure is brought into contact with a mesoporous material so that the metal complex of the phenyl azomethine dendrimer compound is supported by the mesoporous material.