  A neutrino mass matrix model with a bilinear form $M_\nu = k_\nu (M_D
M_R^{-1} M_D^T)^2$ is proposed within the framework of the so-called yukawaon
model, which has been proposed for the purpose of a unified description of the
lepton mixing matrix $U_{PMNS}$ and the quark mixing matrix $V_{CKM}$. The
model has only two adjustable parameters for the PMNS mixing and neutrino mass
atios. (Other parameters are fixed from the observed quark and charged lepton
mass ratios and the CKM mixing.) The model gives reasonable values $\sin^2
2\theta_{12} \simeq 0.85$ and $\sin^2 2\theta_{23} \sim 1$ and $\sin^2
2\theta_{13} \sim 0.09$ together with $R_\nu \equiv \Delta m^2_{21}/\Delta
m^2_{32} \sim 0.03$. Our prediction of the effective neutrino mass $<m>$ in the
neutrinoless double beta decay takes a sizable value $< m >\simeq 0.0034$ eV.
