  The inert Higgs doublet model is an extension of the standard model with an
extra scalar doublet. The extra doublet is $Z_2$ odd while all the other
particles are $Z_2$ even, thus the model contains a dark matter candidate. It
is known that the spin-independent cross section of the dark matter and the
nucleon is highly suppressed for $m_{\text DM} \sim m_h/2$ at the tree level.
In this talk, we show the loop corrections give the significant effects in this
regime.
