An object of the present invention is to provide a plain bearing which can be further improved in bearing capability, in particular, anti-seizure property, initial conformability and cavitation resistance. In the present invention, a sliding layer 2 is formed on the surface of a bearing alloy layer 1 formed of a copper-based or aluminum-based alloy, and the sliding layer 2 comprises a resin binder obtained by applying a strong shearing force to a composition comprising a polybenzimidazole resin as main constituent and at least one member selected from the group consisting of a polyamide-imide resin, a polyamide resin and an epoxy resin, to make the composition into a polymer alloy, and 25 to 75 mass % of a solid lubricant. Owing to such a constitution, toughness and strength are imparted to the sliding layer 2 and the anti-seizure property, initial conformability and cavitation resistance can also be improved.