PURPOSE: To improve the extent of operability in a horn switch of a steering wheel equipped with an air bag unit as well as to reduce the cost of production.

CONSTITUTION: An air bag unit 14 is attached to a steering wheel body 12. This air bag unit 14 consists of a baggy air bag and a plastic cover body 33 or the like. In addition, a face-form switch 48 of a horn switch 41 is set up in space between the air bag and the cover body 33. A fragile tear line 38 is formed on the backside of the cover body 33 after being situated at the outside of a peripheral edge 46c of this face-form switch 48, and likewise a peripheral part 40a of a easily deformable operating part is formed at the surface side of the cover body 33 after being situated in an inner part of the peripheral edge 46c of the switch 48. Accordingly, when a horn operating part 40 is pushed, the operating part peripheral part 40a is deformed to some extent, and thereby the face-form switch 48 is pressable so well in operability. If the air bag is inflated as specified, the switch 48 breaks the tear line, whereby the air bag is smoothly unfoldable.