A horn switch for a steering wheel having an air bag device. The steering wheel includes a multilayer membrane switch as the horn switch in which spacers in one layer are not aligned with the spacers in the other layers. Accordingly, even when the membrane switch is depressed just over one of the spacers in one layer, the electrode plates in the other layers can make contact with each other. Thus the operable area of the membrane switch is enlarged. Further, the membrane switch is supported on its lower surface by a number of ribs which define a number of spaces between the pad lower surface and air bag device. As a result of this space, the operation on the membrane switch can be made resilient in spite of the provision of the air bag device directly under the steering wheel pad. Further, because each part of the pad separated by the air bag device upon impact, each part must be provided with a membrane switch. For this reason, a wiring structure for the two membrane switches is provided such that the manufacture of the pad and the assembly of the steering wheel is more easily facilitated.