  We study the soft supersymmetry (SUSY) breaking terms due to the modulus
F-term in the modular flavor models of leptons. It is found that the soft SUSY
breaking terms are constrained by the modular forms, and specific patterns are
derived. Those phenomenological implications are discussed in such as the
lepton flavor violation, $\mu \rightarrow e + \gamma$ decay. In order to
examine numerically, two modular flavor $A_4$ models are taken. The SUSY
breaking scale is significantly constrained by inputting the observed upper
bound of the $\mu \rightarrow e + \gamma$ decay. The SUSY mass scale is larger
than around $8$ TeV and $5$ TeV for the two $A_4$ models, respectively.
Therefore, the current experimental upper bound for the $\mu \to e + \gamma$
decay corresponds to the new physics of the SUSY particle at the $5$ -- $10$
TeV scale in the modular flavor models. The predicted branching ratio depends
on a modulus $\tau$ significantly. It decreases of one order at the large ${\rm
Im}\,\tau$. We also calculate the branching ratios of tauon decays to $e +
\gamma$ and $\mu + \gamma$. Predicted ones are at most ${\cal O}(10^{-15})$,
which are much below the current experimental bounds.
