A circuit board according to an embodiment of the present invention comprises: a first metal layer; an insulating layer disposed on the first metal layer and comprising boron nitride agglomerate particles coated with a resin; and a second metal layer disposed on the insulating layer, wherein: one of both surfaces of the first metal layer, on which the insulating layer is disposed, is in at least partial contact with one surface of the insulating layer; one of both surfaces of the second metal layer, on which the insulating layer is disposed, is in at least partial contact with the other surface of the insulating layer; a plurality of grooves are formed on a surface which is one of both surfaces of at least one of the first metal layer and the second metal layer and which has the insulating layer disposed thereon; at least some of the particles are arranged in at least some of the plurality of grooves; the width (W) of at least one of the plurality of grooves is 1 to 1.8 times D50 of the particles; and a ratio (D/W) of the depth (D) to the width (W) of at least one of the plurality of grooves is 0.2 to 0.3.