  We construct QCD sum rules for the anti-charmed pentaquark $\Theta_c (3099)$,
recently reported at HERA. The sum rules are constructed similarly with the
$\Theta^+ (1540)$ sum rules using the anti-charmed analogue of the $\Theta^+$
interpolating field. The strange quark and quark-gluon mixed condensates, which
were important in the $\Theta^+$ sum rules, are replaced by the gluon
condensates whose contribution to the OPE is suppressed due to the heavy quark
mass. Our result suggests that the parity of $\Theta_c$ is positive. We
identify the difference from the $\Theta^+$ sum rule, which leads to the
positive parity in this heavy-light pentaquark system. The obtained mass is
similar to the experimental value.
