To provide a sliding member capable of preventing seizure on relative sliding surfaces between a Scotch yoke core and a Scotch choke outer frame even under high speed-high bearing conditions and unusual abrasion.

In this sliding member, even when two sliding flat surfaces having relative reciprocation, using lubricating oil receives a varied load, the two sliding flat surfaces form flat surfaces having no oil groove. At least one sliding flat surface is provided with a lubricating oil supplying hole 8 for supplying lubricating oil. The back surface of the sliding flat surface having the lubricating oil supplying hole 8 forms a relief space part 12 communicating with the lubricating oil supplying hole 8. The relief space part 12 is provided with a means for supplying the lubricating oil.