Various embodiments may relate to an illuminating device. The illuminating device includes a base having a partition board dividing the base into a first accommodating cavity and a second accommodating cavity, a circuit board having light sources and arranged in the first accommodating cavity, and an optical assembly arranged at an opening end of the first accommodating cavity. The partition board, the circuit board and the optical assembly each have at least one air communication structure to enable air from environment to flow into the first accommodating cavity and the second accommodating cavity.