We construct a minimal calculable model of a light dilaton based on the scenario where only top and Higgs sectors are involved in a quasi scale invariant dynamics. The model consistently accommodate the electroweak precision tests even when the Higgs boson is very heavy, thereby allows one to consider a possibility that the particle at around 125GeV, discovered at the LHC experiments, is identified as the light dilaton rather than the Higgs boson. We find that the current LHC data allow distinct parameter regions where the observed particle is either mostly the Higgs boson or the dilaton.