A metal-clad laminated board includes an insulating layer and a metal layer in contact with at least one surface of the insulating layer. The insulating layer includes a cured product of a thermosetting resin composition containing a reaction product of a polyphenylene ether and an epoxy compound. The polyphenylene ether has 1.5 to 2 hydroxyl groups on average in one molecule, and the epoxy compound has 2 to 2.3 epoxy groups on average in one molecule. In the metal-clad laminated board, the reaction product has a terminal hydroxyl group concentration of 700 μmol/g or less. The metal layer includes a metal substrate and a barrier layer containing cobalt. The barrier layer is provided on the metal substrate at a side close to a contact surface of the metal layer with the insulating layer. The contact surface has surface roughness of 2 μm or less in ten-point average roughness Rz.