An illuminating apparatus (20) includes a lamp cover (200), a solid-state light emitting component (23) and an air tank (24). The lamp cover has a first end and an opposite second end. The lamp cover tapers from the first end to the second end. The lamp cover defines therein an air channel (25) running from the first end to the second end of the lamp cover. The solid-state light emitting component is disposed in the lamp cover at the second end thereof. The air tank has a chamber (240) therein in thermally contact with the solid-state light emitting component. The air tank has a plurality of first and second air vents (244, 245). The chamber is communicated with the air channel via the first air vents, and is communicated with an ambient environment via the second air vents. The first and second air vents are disposed at different altitudes.