A micro-light-emitting diode device includes a first semiconductor layer, an active layer, and a second semiconductor layer. The first semiconductor layer has a first bottom surface. The active layer is disposed on the first semiconductor layer. The second semiconductor layer is disposed on the active layer. The second semiconductor layer and the active layer have an interface. A surface of the second semiconductor layer opposite to the active layer is a light-exiting surface of the micro-light-emitting diode device. A distance between the light-exiting surface and the interface decreases from a central axis of the second semiconductor layer to an edge of the second semiconductor layer, so as to provide a focusing effect for the light by the light-exiting surface.