is larger than this value the pressing force in the radial direction increases and there is a danger that smooth rotation cannot be obtained even if the cage is made of a self lubricating resin material fig4 shows the results of bearing life tests in fig4 u201c comparative example 1 u201d in the u201c bearing u201d column is a typical conventional tapered roller bearing with a cage that is spaced from the outer ring u201c embodiment 1 u201d is a tapered roller bearing according to the present invention the roller coefficient u03b3 of which is greater than 0 94 being different from the conventional bearing only in this respect u201c embodiment 2 u201d is another tapered roller bearing according to the present invention the roller coefficient u03b3 of which is greater than 0 94 and the window angle of which is set in the range of 55 u00b0 to 80 u00b0 the tests were conducted under severe lubrication and excessive load conditions as clarified in the figure the life of u201c embodiment 1 u201d is more than twice the life of u201c comparative example 1 u201d furthermore the life of u201c embodiment 2 u201d is approximately five or more times the life.