A slide bearing (1) provided and configured to support a crankshaft or a crankpin includes: a halved upper bearing body (10) which is disposed on the upper side in an up-and-down movement direction ofa piston; and a halved lower bearing body (20) which is disposed on the lower side in the up-and-down movement direction. The upper bearing body (10) includes an upper sliding surface (12) having anupper oil groove (14) disposed along a circumferential direction of the upper sliding surface (12) at a central portion in an axial direction of the upper sliding surface (12). The lower bearing body(20) includes a lower sliding surface (22) that configures, along with the upper sliding surface (12), a cylindrical sliding surface that rotatably supports the crankshaft or the crankpin through an oil film, and the axial width of the lower sliding surface (22) is narrower than the axial width including the oil groove (14) of the upper sliding surface (12).