  We report a coexistence of superconductivity and antiferromagnetism in
five-layered compound HgBa$_2$Ca$_4$Cu$_5$O$_y$ (Hg-1245) with $T_c=108$ K,
which is composed of two types of CuO$_2$ planes in a unit cell; three inner
planes (IP's) and two outer planes (OP's). The Cu-NMR study has revealed that
the optimallydoped OP undergoes a superconducting (SC) transition at $T_c=108$
K, whereas the three underdoped IP's do an antiferromagnetic (AF) transition
below $T_N\sim$ 60 K with the Cu moments of $\sim (0.3-0.4)\mu_B$. Thus bulk
superconductivity with a high value of $T_c=108$ K and a static AF ordering at
$T_N=60$ K are realized in the alternating AF and SC layers. The AF-spin
polarization at the IP is found to induce the Cu moments of $\sim0.02\mu_B$ at
the SC OP, which is the AF proximity effect into the SC OP.
