A sliding bearing (1) includes an upper casing (3) which is made of polyacetal resin as a synthetic resin, has an annular surface (2), and serves as a first bearing body; a second bearing body (5) which is made of a synthetic resin, is superposed on the upper casing (3) so as to be rotatable about an axis (O), and has an synthetic resin-made annular surface (4) opposed to the annular surface (2); and a synthetic resin-made annular sheet (6) which is interposed between the annular surfaces (2) and (4) and slidably abuts against at least one of the upper casing (3) and the bearing body (5).