The invention discloses an indicating/alarming apparatus which includes an optically transparent polymer plate, a light-shielding layer, a flexible circuit board, a plurality of light-emitting devices and a light-reflecting layer. The light-shielding layer is formed to overlay an upper surface of the optically transparent polymer plate. The plurality of light-emitting devices are soldered on the flexible circuit board. The flexible circuit board is mounted on a lower surface of the optically transparent polymer plate such that the plurality of light-emitting devices are disposed within an opening formed on the lower surface of the optically transparent polymer plate. Each light-emitting device emits a light entering from a light incident face of the opening into the optically transparent polymer plate which guides, due to total reflection, the light to exit from a top side surface, a bottom side surface, a first edge surface, a second edge surface and sites on surfaces whose total reflection is broken. The light-reflecting layer is formed to overlay the lower surface of the optically transparent polymer plate to reflect the light.