We show recent results of dark photon and dark-sector particles at Belle. In particular, we present the following searches: for dark photon and dark Higgs via Higgsstrahlung, for a dark gauge boson coupling predominantly to quarks in $\eta$ decays, and for $D^0$ decays to invisible final states. The data are produced in $e^+ e^-$ collisions at the KEKB asymmetric-energy collider and collected with the Belle detector.