Because the Arches cluster is located very near in the Galactic center of extreme environments,it has been suspected to have a shallower initial mass function(IMF)with an elevated low-mass cutoff,compared to the Galactic disk clusters.Although several highresolution photometries have lowered the 50%completeness limit mass down to~1.3M⊙,resolving fainter stars than~1.3M⊙ will have to await until the next-generation infrared space telescope or an extremely large ground telescope is available.We devise a novel photometry method to estimate the shape of the low-end mass function(MF)where the individual stars are not resolved by fitting the pixel intensity histograms(PIHs)of the artificial images to the observed PIH.Applying this method to the Arches cluster,we found that the IMF of the Arches cluster should not have an elevated cutoff mass than higher 0.1 M⊙ and not be too different that for the Galactic disk clusters.