A simple model for efficiency analysis of daily operation in proton radiotherapy is applied to numerical calculation with fixed time advancing. For the simplifying, man power is assumed to be enough and troubles in the equipments are ignored. To generate random numbers which become the time for adjusting the patient position and for waiting the next patient, typical probability distributions are utilized in the simulation. By using the simulation, treatment capacity of a facility is estimated for different number of treatment rooms to know the efficient number of gantries for proton radiotherapy.