Résumé
Here we study naturalness problem in a type II seesaw model, and show that the Veltman condition modified (mVC) by virtue of the additional scalar charged states is satisfied at one loop within a region of the allowed parameter space of the model. The latter is severely constrained by unitarity and boundedness from below as well as by consistency with the diphoton Higgs decay data of the LHC run 1. In this context, our analysis of the naturalness condition affects dramatically the masses of heavy Higgs bosons $H^0$, $A^0$, $H^\pm$ and $H^{\pm\pm}$, reducing the ranges of variation of $m_{H^\pm}$ and $m_{H^{\pm\pm}}$ with an upper bounds at 288 and 351 GeV, respectively, while the neutral Higgs bosons $H^0$, $A^0$ are found to be almost degenerate at about 207 GeV.