  For the purpose of deriving the observed nearly tribimaximal neutrino mixing,
a possible yukawaon model in the quark sector is investigated. Five observable
quantities (2 up-quark mass ratios and 3 neutrino mixing parameters \sin^2
2\theta_{atm}, \tan^2\theta_{solar} and |U_{13}|) are excellently fitted by two
parameters (one in the up-quark sector and another one in the right-handed
Majorana neutrino sector).
