Electron cyclotron heating (ECH) power modulation experiments in the GAMMA 10 tandem mirror have been started in order to generate and control the high heat flux and to make the ELM (edge localized mode) like intermittent heat load pattern for divertor simulation studies. ECH for potential formation at the plug region (P-ECH) produces the electron flow with high energy along the magnetic filed line. The peak heat-flux of more than 10 MW/m2 was obtained during the ECH injection within the available power of ECH. It is found that arbitrary intermittent heat flux is possible by modulating the ECH power. 0.05 MJ/m2 heat pulse has been obtained with 380 kW 5ms ECH pulse, which indicates possibility of 0.5 MJ/m2 level with multi-MW ECH power.