Today, in many cases bearing is used. And bearing which can use under high-speed rotation or small spaces is needed. Grease is most popular lubricant used small ball bearing. Type oh grease and enclosed capacity of grease affect ability about small ball bearing, so this experiment investigate how much grease are needed under high -speed rotation every viscosity and amount of grease, and ability difference from viscosity and amount of grease. As the conclusion, amount of grease to converge fixed amount, and greater viscosity grease has much fixed amount. But ability difference from viscosity of grease is very small. And bearing which has10mg grease (standard amount is 50mg) can use 2000 hours.