Disclosed is a cemented carbide comprising 5 to 10 mass % of cobalt and/or nickel, and 0 to 10 mass % of at least one selected from a carbide (except for tungsten carbide), a nitride and a carbonitride of at least one selected from the group consisting of metals of groups 4, 5 and 6 of the Periodic Table, the balanced amount of tungsten carbide, a hard phase comprising mainly tungsten carbide particles, and containing β particles of at least one selected from the carbide, the nitride and the carbonitride, and the hard phase being bonded through a binder phase comprising mainly cobalt and/or nickel, wherein a mean particle size of the tungsten carbide particles is 1 μm or less, and the cemented carbide having a sea-island structure in which plural binder-phase-aggregated portions composed mainly of cobalt and/or nickel are scattered in the proportion of 10 to 70 area % based on the total area on the surface of the cemented carbide. The cemented carbide is excellent in wear resistance and fracture resistance.