Constraints to Dark Matter from Inert Higgs Doublet Model

We study the Inert Higgs DoubletModel and its inert scalar Higgs H as the only source for dark matter. It is found that three mass regions of the inert scalar Higgs can give the correct dark matter relic density. The low mass region ( between 3 and 50GeV) is ruled out. New direct dark matter detection experiments will probe the intermediate ( between 60 and 100GeV) and high ( heavier than 550GeV) mass regions. Collider experiments are advised to search for D-+/- -> HW +/- decay in the two jets plus missing energy channel.