The Fermi coupling constant can be determined with high precision by measuring the muon lifetime. Therefore, it has played an essential role in testing the Standard Model and searching for new physics. The positive muon lifetime is obtained by a time measurement of decay positrons. The statistical uncertainty limited the most precise result to date, so an experiment with an intense pulsed muon beam has the potential to improve the precision further. However, the signal pulse-pileup associated with instantaneous high counting rate is an obstacle in pulsed beams experiments. This paper proposes a new experiment to measure the muon lifetime using a pulsed muon beam at J-PARC and a segmented positron detector.