To properly predict a lift matching an actual rolling bearing life.
After an equivalent load P is computed from characteristics information of the rolling bearing, a reliability coefficient a1 is decided, and a lubrication parameter aL matching a used lubricant is computed. A contamination degree coefficient aC is decided while taking a material coefficient into consideration, and a load parameter {(P-Pu)/C}.1/aC is computed after a fatigue limit load Pu is computed on the basis of the characteristics information. On the basis of the lubrication parameter aL and the load parameter {(P-Pu)/ C}.1/aC, a life time correction coefficient aNSK is computed by referring to a life correction coefficient computing map, and then, a bearing life LA is computed according the following expression, LA=a1.aNSK.(C/P)p.
MURAKAMI YASUO