In lubricated reciprocating rolling contact, a cavity generated in the outlet region can have a significant effect on the oil-film formation. An estimation equation for the length of cavity enclosed in oil meniscus in steady state pure rolling contact was previously derived. The numerical simulation procedure is now extended to the reciprocating motion to calculate the changes of cavity length and oil film thickness. The ratio of oil film thickness to gap height in a cavity was measured by an optical interferometric method. EHL numerical simulation for reciprocating pure rolling contact was conducted using the extended Reynolds equation. This is an abstract of a paper presented at the 2009 World Tribology Congress (Kyoto, Japan 9/6-11/2009).