  Muon spin relaxation measurements on the filled skutterudite compound
SmRu4P12 have been carried out in zero- and longitudinal-fields. Temperature
dependence of both initial asymmetry and muon-spin depolarization rate show the
appearance of a magnetically ordered state below the metal-insulator transition
temperature TMI. The present study indicates that the ordering below TMI is not
a non-magnetic antiferro-quadrupolar ordering but a magnetic one, which
supports a scenario that a magnetic octupolar ordering occurs below TMI in
SmRu4P12.
