  We report an experimental determination of the isospin of
$\Lambda_c(2765)^+/\Sigma_c(2765)^+$ using 980 fb$^{-1}$ data in the $e^+e^-$
annihilation around $\sqrt{s} = 10.6$ GeV collected by the Belle detector
located at the KEKB collider. The isospin partners are searched for in the
$\Sigma_c(2455)^{++/0} \pi^{0}$ channels, and no evidence was obtained. Thus
the isospin is determined to be zero, and the particle is established to be a
$\Lambda_c$.
