An external load applied to a roller bearing is distributed among the rolling elements. This distribution of the rolling element load changes according to the axial clearance of the bearing, and will affect the rolling contact fatigue life of the bearing. In this study, the rolling element load was measured using an optical fiber sensor that was inserted into one of the rollers in the double row tapered roller bearing to be measured, and the effect of the axial clearance on the rolling element load was investigated. As a result, it was clarified that the load distribution factor decreases as axial clearance increases.