A lamp comprises a housing, a heat sink, a fan and a light-emitting element. The housing includes an opening end and a compartment communicating with the opening end. The heat sink is disposed at the opening end and includes a lateral wall, a base, a plurality of first connection members, a plurality of first air channels and at least one second air channel. The base is surrounded by and spaced from the lateral wall. The base is connected to an inner circumferential wall of the lateral wall via the first connection members, wherein each of the first air channels is formed between adjacent two of the first connection members. The at least one second air channel is formed between an outer circumferential wall of the lateral wall and an inner face of the housing. The fan is disposed at one side of the heat sink in the compartment. The light-emitting element is disposed at another side of the heat sink.