  We calculate the invariant-mass distribution for the cc-bar pair produced in
the inclusive Upsilon(1S) decay based on the color-singlet mechanism of the
nonrelativistic quantum chromodynamics factorization approach at leading order
in the bottom-quark velocity v_b in the meson rest frame. As the short-distance
processes, we consider bb-bar -> g^*gg followed by g^* -> cc-bar and bb-bar ->
gamma^* -> cc-bar at leading order in the strong coupling. The invariant-mass
distribution of the bb-bar -> cc-bar gg contribution has a sharp peak just
above the threshold and that of the bb-bar -> gamma^* -> cc-bar channel is
concentrated at the maximally allowed kinematic end point. We predict that
Gamma[Upsilon(1S) -> cc-bar+X]/Gamma[Upsilon(1S)->light hadrons] = 0.065
alpha_s, which is smaller than a previous result by about 20%.
