An induction device includes a first core made of a ferrite material, a second core made of a material having a lower magnetic permeability than the ferrite material and a higher saturation magnetic flux density than the ferrite material, a cooling device and a coil. The first core and the second core cooperate to form a closed magnetic circuit. The first core includes a contact surface cooled by the cooling device and a first magnetic leg extending so as to intersect with the contact surface and toward the second core. The second core includes a second magnetic leg extending so as to intersect with the contact surface and toward the first core and disposed to be wound around by the coil.