  The properties of open strange meson $K_1^\pm$ in nuclear matter are
estimated in the QCD sum rule approach. We obtain a relation between the
in-medium mass and width of $K_1^-$ ($K_1^+$) in nuclear matter, and show that
the upper limit of the mass shift is as large as -249 (-35) MeV. The spectral
modification of the $K_1$ meson is possible to be probed by using kaon beams at
J-PARC. Such measurement together with that of $K^*$ will shed light on how
chiral symmetry is partially restored in nuclear matter.
