I discuss cosmological implications of the Higgs field in inflationary cosmology in two separate cases, namely, in the case it is a subdominant ingredient during inflation and in the case inflation is driven by the Higgs field itself. In the former case long-wave quantum fluctuations produces the Higgs condensation during inflation which produces too large curvature perturbations in some types of inflation models, or may induce
modulated reheating. As for the latter case, while there are a number of Higgs inflation models proposed so far, I argue that all these models are unified in the context of the generalized G inflation, and observational implications of Higgs G inflation is discussed.