A key switch apparatus is provided. The key switch apparatus includes a key base, a key cap, and a collapsible linking assembly extending between the key cap and the key base. The linking assembly is reconfigurable between extended and collapsed positions for displaceably supporting the key cap relative to the key base. The linking assembly includes pivotally coupled first and second linking members. The first linking member is provided with a flexible member that is resiliently biased to bulge transversely outward toward the key cap when the linking assembly is disposed in the extended position. The second linking member is formed with a press member that maintains contact with the flexible member, such that it transversely deflects the flexible member inward toward the key base responsive to the application of a pressing force upon the key cap. The second linking member is biased by the flexible member to restore the linking assembly to its extended position upon removal of the pressing force from the key cap.