Illuminated push-button switch having fixed member and keyboard including same

An illuminated push-button switch comprising:

• a push-button including a plunger body having a plunger through hole, wherein the plunger body comprises a push-button upper-surface of the push-button at an upper end of the plunger through hole;
• a covering member configured to cover at least the push-button upper-surface of the push-button and having a covering member upper-surface wall receiving light from below the push-button through the plunger through hole of the push-button, wherein the plunger through hole extends from a push-button bottom-surface to the push-button upper-surface, and the plunger through hole has a larger opening area on the push-button upper-surface than an opening area on the push-button bottom-surface;
• a contact unit configured to be set on or off via the push-button by pushing the covering member upper-surface wall;
• and
• a plurality of supporting fix members fixing the covering member to the plunger body of the push-button and forming an unoccupied space between the covering member upper-surface wall of the covering, member and the push-button upper-surface of the plunger body, wherein
• the plurality of supporting fix members are provided, separated from each other, in a plane perpendicular to an optical axis.