  The magnetic and electronic properties of Ba$_4$Ru$_3$O$_{10}$ were
investigated by the ab-initio and model calculations. It is shown that
nonmagnetic ground state of the one-third Ru$^{4+}$ ions is not due to the
correlation effects. It is rather caused by the charge disproportionation
between crystallographically different Ru and the molecular orbital formation
in the Ru's trimer.
