
We investigate how accurately the total mass of neutrinos is constrained from the magnitude dispersion of SNe Ia due to the effects of gravitational lensing. For this purpose, we use the propagation equation of light bundles in a realistic inhomogeneous universe. With a fitting formula for the nonlinear matter power spectrum taking account of the effects of massive neutrinos, we find that in our model it is possible to obtain the upper imit ~1.0 eV for future optical imaging surveys with the WideField InfraRed Survey Telescope and Large Synoptic Survey Telescope. Furthermore, we discuss how deep we need to observe SNe Ia and to what extent we have to reduce the magnitude error except for lensing in order to realize the current tightest limit _m_ < 0.2[eV]. 
