  According to an idea that effective Yukawa coupling constants Y_f^{eff} are
given vacuum expectation values < Y_f> of fields ("Yukawaons") Y_f as
Y_f^{eff}=y_f < Y_f>/\Lambda, a possible superpotential form in the charged
lepton sector under a U(3) [or O(3)] flavor symmetry is investigated. It is
found that a specific form of the superpotential can lead to an empirical
charged lepton mass relation without any adjustable parameters.
