  Let $M$ be an $n$-dimensional complete simply connected Riemannian manifold
with sectional curvature bounded above by a nonpositive constant $-\kappa^2$.
Using the cone total curvature $TC(\Gamma)$ of a graph $\Gamma$ which was
introduced by Gulliver and Yamada Math. Z. 2006, we prove that the density at
any point of a soap film-like surface $\Sigma$ spanning a graph $\Gamma \subset
M$ is less than or equal to $\frac{1}{2\pi}\{TC(\Gamma) -
\kappa^{2}\area(p\mbox{$\times\hspace*{-0.178cm}\times$}\Gamma)\}$. From this
density estimate we obtain the regularity theorems for soap film-like surfaces
spanning graphs with small total curvature. In particular, when $n=3$, this
density estimate implies that if \begin{eqnarray*} TC(\Gamma) < 3.649\pi +
\kappa^2 \inf_{p\in M} \area({p\mbox{$\times\hspace*{-0.178cm}\times$}\Gamma}),
\end{eqnarray*} then the only possible singularities of a piecewise smooth
$(\mathbf{M},0,\delta)$-minimizing set $\Sigma$ is the $Y$-singularity cone. In
a manifold with sectional curvature bounded above by $b^2$ and diameter bounded
by $\pi/b$, we obtain similar results for any soap film-like surfaces spanning
a graph with the corresponding bound on cone total curvature.
