A coil component comprising: a coil winding; and an insulating member having electrical insulation properties and integrally formed with the coil winding (2,) so as to cover a part of a surface of the coil winding, the coil component being adapted to be sandwiched by magnetic core members (8, 9) in a direction of winding axis of the coil winding, wherein the coil winding is composed of a plurality of plate-like coil members (10, 12) in a ring shape having ends joined together in a stacking direction with a clearance there between so as to be continuous in a predetermined winding direction; wherein the insulating member covers outermost plate surfaces of the coil members (10, 12) facing the magnetic core members (8, 9) once the coil component is sandwiched between the magnetic core members (8,9), a space between the adjacent coil members, and inner perimeter edges of the coil members (10, 12), and has a portion defining an opening (52, 54) along the direction of winding axis of the coil winding; the insulating member is provided with an outwardly protruding convex portion (50a, 50b) configured to position the corresponding magnetic core member on one surface thereof facing the magnetic core member, characterized in that each of the coil members is provided with a protrusion (36, 34) outwardly bulged at a position different from its terminals (24, 26) such that a part of an outer perimeter edge thereof is larger in a radial direction; a part of a surface (34a, 34b, 36a, 36b) of the protrusion is exposed without being covered with the insulating member; circumferential positions of the protrusions (36, 34) provided to the plurality of coil members (10, 12) differ from one another. a coil winding; and an insulating member having electrical insulation properties and integrally formed with the coil winding (2,) so as to cover a part of a surface of the coil winding, the coil component being adapted to be sandwiched by magnetic core members (8, 9) in a direction of winding axis of the coil winding, wherein the coil winding is composed of a plurality of plate-like coil members (10, 12) in a ring shape having ends joined together in a stacking direction with a clearance there between so as to be continuous in a predetermined winding direction; wherein the insulating member covers outermost plate surfaces of the coil members (10, 12) facing the magnetic core members (8, 9) once the coil component is sandwiched between the magnetic core members (8,9), a space between the adjacent coil members, and inner perimeter edges of the coil members (10, 12), and has a portion defining an opening (52, 54) along the direction of winding axis of the coil winding; the insulating member is provided with an outwardly protruding convex portion (50a, 50b) configured to position the corresponding magnetic core member on one surface thereof facing the magnetic core member, characterized in that each of the coil members is provided with a protrusion (36, 34) outwardly bulged at a position different from its terminals (24, 26) such that a part of an outer perimeter edge thereof is larger in a radial direction; a part of a surface (34a, 34b, 36a, 36b) of the protrusion is exposed without being covered with the insulating member; circumferential positions of the protrusions (36, 34) provided to the plurality of coil members (10, 12) differ from one another.