PROBLEM TO BE SOLVED: To suppress the outflow of a lubricant for oil lubrication bearings.SOLUTION: A lubricant outflow suppressing device for a rotary machine, which comprises a main shaft extending in an axial direction, and bearings rotatably supporting the main shaft and using a lubricant, comprises: a bearing cover 60 for covering one side of the bearing and having a through hole formed therein for allowing the main shaft to pass therethrough in an axial direction; and an oil thrower ring 70 provided along a circumferential direction on an outer circumference of the main shaft and arranged between a bearing 52 and the bearing cover 60. An oil relief groove 62 is formed in a portion facing the bearing within the internal surface of the bearing cover 60, the groove surrounding the outside of the through hole at least at a position higher than the center of the through hole.
