  We propose a model of neutrino mass matrix with large $SU(2)$ multiplets and
gauged $U(1)_{L_\mu - L_\tau}$ symmetry, in which we introduce $SU(2)$ quartet
scalar and quintet fermions with nonzero $L_\mu - L_\tau$ charge. Then we
investigate the neutrino mass structure and explore phenomenologies of large
multiplet fields at the collider, particularly, focussing on doubly- and
singly- charged exotic leptons from the quintet.
