Generally, in metalworking fluids including cutting oils, mineral oils are often used as base stocks. In addition, extreme pressure additives containing sulfur are blended to improve the cutting performance. Recently, in order to raise the flash point and to reduce the fire risk, there is an increasing demand for lubricants where esters having sufficiently high flash points, compared with those of mineral oils, are used as base stocks. However, little has been published regarding the effectiveness of the organo-sulur compounds in esters. In this study, sulfurized olefin and sulfurized ester in an ester base stock were evaluated based on both the cutting performance and the anti-seizure property. In the cutting performance evaluation, the tapping test results indicated that there was no significant difference between sulfurized olefin and sulfurized ester in ester, although the previous study suggested sulfurized ester were superior to sulfurized olefin in mineral oil. On the other hand, in the anti-seizure property evaluation, the results obtained by the Falex pin and vee block method demonstrated that the lubricating effects of those organo-sulfur compounds were depended on the type of the base stock, that is, mineral oil or ester.