A steering wheel airbag apparatus may include: a mounting plate seated on a wheel armature, and having a guide pipe formed therein; a cover coupled to the mounting plate; a moving contact module movably installed in the guide pipe, pressurized and moved by the cover, and connected to a positive electrode; and an elastic contact portion coupled to the guide pipe, connected to a negative electrode while supported by the negatively charged wheel armature, and connected to the moving contact module as the moving contact module is moved.