A coil structure comprising: a base plate including a coil conductor; a first core disposed on one main surface side of the base plate; a second core disposed on other main surface side of the base plate; and an insulating member made of an insulating material, wherein the first core includes: a main body part extending in a first direction along a main surface of the base plate; a first foot part extending from the main body part to the second core through the base plate; and a second foot part extending from the main body part to the second core through the base plate at a position such that the coil conductor is sandwiched between the second foot part and the first foot part in the first direction, and the insulating member includes: a bottom wall part interposed between at least the first foot part and the second core; and a side wall part extending along at least either of the first foot part and the second foot part and interposed between either of the foot parts (7A, 8) and the coil conductor; wherein a heat dissipation material is disposed in a gap between the second foot part and the second core, and the heat dissipation material is made of a material having a higher thermal conductivity than the insulating member. a base plate including a coil conductor; a first core disposed on one main surface side of the base plate; a second core disposed on other main surface side of the base plate; and an insulating member made of an insulating material, wherein the first core includes: a main body part extending in a first direction along a main surface of the base plate; a first foot part extending from the main body part to the second core through the base plate; and a second foot part extending from the main body part to the second core through the base plate at a position such that the coil conductor is sandwiched between the second foot part and the first foot part in the first direction, and the insulating member includes: a bottom wall part interposed between at least the first foot part and the second core; and a side wall part extending along at least either of the first foot part and the second foot part and interposed between either of the foot parts (7A, 8) and the coil conductor; wherein a heat dissipation material is disposed in a gap between the second foot part and the second core, and the heat dissipation material is made of a material having a higher thermal conductivity than the insulating member. a main body part extending in a first direction along a main surface of the base plate; a first foot part extending from the main body part to the second core through the base plate; and a second foot part extending from the main body part to the second core through the base plate at a position such that the coil conductor is sandwiched between the second foot part and the first foot part in the first direction, and the insulating member includes: a bottom wall part interposed between at least the first foot part and the second core; and a side wall part extending along at least either of the first foot part and the second foot part and interposed between either of the foot parts (7A, 8) and the coil conductor; wherein a heat dissipation material is disposed in a gap between the second foot part and the second core, and the heat dissipation material is made of a material having a higher thermal conductivity than the insulating member. a bottom wall part interposed between at least the first foot part and the second core; and a side wall part extending along at least either of the first foot part and the second foot part and interposed between either of the foot parts (7A, 8) and the coil conductor;