J-PARC neutrino experiments use the proton beam to produce intense $\nu_{\mu}$ beam. One of the motivations of the experiment is to discover the CP violation in the lepton sector. The J-PARC muon monitor (MUMON) is one of the monitors and the only one to monitor the secondary beam bunch-by-bunch, therefore MUMON is essential for the beam operation. The experiment is planning to increase the proton beam power in the near future. Current MUMON detectors do not have high radiation tolerance. We need to develop new detectors for future high-intensity beam. Candidates are diamond detectors, PMT (Photon Multiplier Tube) and EMT (Electron Multiplier Tube). According to data so far, EMT is the best candidate. Initial test results are shown and the next beam test plan is introduced in this talk.