Production and control of electron cyclotron resonance (ECR) plasma for volume sources have been studied and preliminary results are presented. Effects of magnetic filter in ECR plasmas are discussed by comparing with ones in DC plasmas. Electron energy distribution in DC plasma is well controlled with the use of the magnetic filter. In ECR plasmas, however, electron cooling due to the magnetic filter in the extraction region is not so effective as ones in DC plasmas. ©1998 American Institute of Physics.