High field ESR measurements of Me4As[Pd(dmit)2]2

High field ESR measurements of Mott-Hubbard insulator Me 4 As[Pd(dmit) 2 ] 2 have been performed in the frequency region from 50 to 315 GHz using the pulsed magnetic field up to 15 T. Broad and sharp resonances were observed in the temperature region from 1.8 to 77 K. The origins of these resonances were discussed from the temperature and frequency dependences in connection with the antiferromagnetic order suggested by H-NMR at 35 K.