  We confront admixture of dark matter inside neutron star using gravitational
wave constraints coming from binary neutron star merger. We consider a
relativistic mean field model including $\sigma-\omega-\rho$ meson interaction
with NL3 parameterization. We study fermionic dark matter interacting with
nucleonic matter via Higgs portal mechanism. We show that admixture of dark
matter inside the neutron star soften the equation state and lower the value of
tidal deformability. Gravitational wave GW170817 observation puts an upper
bound on tidal deformability of a binary neutron star with low spin prior at
90\% confidence level, which disfavors stiff equation of state such as Walecka
model with NL3 parameterization. However, we show that Walecka model with NL3
parameterization with a fermionic dark matter component satisfy the tidal
deformability bound coming from the GW170817 observation.
