A highly thermally conductive printed circuit board prevents electrochemical migration by inhibiting elution of copper ions. The printed circuit board is a metal-base printed circuit board including a metal base plate having an insulating resin layer and a copper foil layer stacked thereon in this order. In the printed circuit board, the insulating resin layer contains a first inorganic filler made of inorganic particles having particle diameters of 0.1 nm to 600 nm with an average particle diameter (D50) of 1 nm to 300 nm, and a second inorganic filler made of inorganic particles having particle diameters of 100 nm to 100 μm with an average particle diameter (D50) of 500 nm to 20 μm, and the first inorganic filler and the second inorganic filler are uniformly dispersed in the insulating resin layer.