the authors verified an anisotropic grain growth mechanism of CuFeO 2 in microwave processing by comparative experiments using multimode and single-mode microwave irradiation furnace. Anisotropic grain growth of CuFeO 2 was promoted in multimode processing with continuous wave, but not with pulse wave. On the other hand, in single-mode processing, pulse wave was promoted anisotropic grain growth. In microwave E-field irradiation, it is considered that anisotropic grain growth was promoted by increasing the solid phase diffusion due to electric fields increase around the powder interface. In microwave H-field irradiation, it is considered that local heating around the powder interface resulted in diffusion promotion and anisotropic grain growth was occurred.