  Dark matter Axion search with riNg Cavity Experiment (DANCE) was proposed to
search for axion dark matter [Phys. Rev. Lett. 121, 161301 (2018)]. We aim to
detect the rotation and oscillation of optical linear polarization caused by
axion-photon coupling with a bow-tie cavity. DANCE can improve the sensitivity
to axion-photon coupling constant $g_{a \gamma}$ for axion mass $m_a <
10^{-10}~\rm{eV}$ by several orders of magnitude compared to the best upper
limits at present. A prototype experiment DANCE Act-1 is ongoing to demonstrate
the feasibility of the method and to investigate technical noises. The optics
was assembled and the performance of the cavity was evaluated. The first 12-day
observation was successfully performed in May 2021. We reached $3 \times
10^{-6}~\rm{rad/\sqrt{Hz}}$ at $10~\rm{Hz}$ in the one-sided amplitude spectral
density of the rotation angle of linear polarization.
