A microwave resonator is fabricated by a lump of spherical metal particles for the first time. It is the evidence that those particles constitute artificial dielectrics. The effective permittivity is calculated numerically together with the permeability. Resonant mode frequencies in the experiment are compared with the theoretical result obtained by the effective material constants above. Their reasonable agreement indicates the validity of material constant extraction. The unique diamagnetism of spherical particles could be utilized for improvement of spurious property of a resonator.