ELECTRONIC COMPONENT INCLUDING PLANAR TRANSFORMER

An electronic component 100 includes: a circuit board module 104 which is composed of a plurality of layers, and in which a primary circuit 120 and secondary circuits 122, 124 are each formed using wring patterns of a first layer L1 to an eighth layer L8; and a magnetic core 106 which magnetically couples the primary circuit 120 and the secondary circuits 122, 124. The circuit board module 104 includes: cutout portions 104b which are formed in a cutout shape from side edge portions toward an inner side and which position the magnetic core 106 at a predetermined attachment position in a state of housing the magnetic core 106; and widened portions 104c which continue from the cutout portions 104b and are formed in a cutout shape from the side edge portions toward the inner side of the circuit board module 104, and which are formed on sides of the magnetic core 106 so as to be larger than a width W1 for housing of the cutout portions 104b.