PURPOSE: To prevent occurrence of leak by forming the surface of a sliding member so as to assure a specific coarseness of center line and relative load length value.

CONSTITUTION: High-purity Al2O3 having about 20μm grain diameter is processed into a disk by cold isostatic pressure molding and then the disk is burned at 1600-1700°C to prepare a ceramic sliding member. The sliding member is subjected for a prescribed time to lapping for sliding free abrasive grain having a prescribed grain size on a lapping machine to provide the objective sliding member made of ceramic, wherein average coarseness (Ra) of center line on the sliding face is expressed by 0.15μm≤Ra≤0.40μm and relative load length value tp in 0.5μm cut depth expressed by the formula [(total length contained in 0.5μm cut depth/all measuring distance L)×100] is expressed by 0%≤t≤90%. The sliding member is used for a part which comes into contact with a flexible member such as a resin material or a rubber material. Since the sliding member is excellently familiar with the flexible member, occurrence of leak is prevented.