  We consider two Higgs doublet models (THDMs) with both the Higgs potential
and Yukawa interactions being aligned, which we call "double-aligned THDMs". In
this scenario, coupling constants of the discovered Higgs boson to the Standard
Model (SM) particles are identical to those of the SM Higgs boson, and flavor
changing neutral currents via neutral Higgs bosons do not appear at tree level.
We investigate current constraints and future prospects of the model by using
measurements from flavor experiments and data of multi-lepton final states at
LHC. Especially, we focus on the electroweak pair production of the additional
Higgs bosons with their masses below $2m_t$. We find that the most of the
parameter space are already excluded by the current LHC data when the leptonic
decays of the additional Higgs bosons are dominant, which can be interpreted to
the scenario in the Type-X THDM as a special case. We also clarify the
parameter region where the high-luminosity LHC can explore, and demonstrate the
reconstruction of the masses of additional Higgs bosons from the
$b\bar{b}\tau^+\tau^-$ final states in a few benchmark points.
