  We report the discovery of an annular emission of $\sim$3'-9' radius around
the center of a transient source, an X-ray burster MAXI J1421-613, in the
Suzaku follow-up analysis. The spectrum of the annular emission shows no
significant emission-line structure, and is well explained by an absorbed power
law model with a photon index of $\sim$4.2. These features exclude the
possibility that the annular emission is a shell-like component of a supernova
remnant. The spectral shape, the time history, and the X-ray flux of the
annular emission agree with the scenario that the emission is due to a
dust-scattering echo. The annular emission is made under a rare condition of
the dust-scattering echo, where the central X-ray source, MAXI J1421-613,
exhibits a short time outburst with three X-ray bursts and immediately
re-enters a long quiescent period. The distribution of the hydrogen column
density along the annular emission follows that of the CO intensity, which
means that MAXI J1421-613 is located behind the CO cloud. We estimate the
distance to MAXI J1421-613 to be $\sim$3~kpc assuming that the dust layer
responsible for the annular emission is located at the same position as the CO
cloud.
