A smoke detector, comprising: a housing (2, 7); a sensing chamber (4, 5, 6) in the housing, wherein in the sensing chamber, a first light emitter and a first light receiver are disposed at the periphery of the sensing chamber and facing a middle portion of the sensing chamber, the first light emitter and the first light receiver being arranged at a central angle between 90° and 180°; a first baffle in the sensing chamber, the first baffle being disposed adjacent to the first light emitter and including a baffle body and a branch portion, the baffle body extending from the periphery of the sensing chamber toward the middle portion, and the branch portion including a plurality of sub-baffles (4221, 4222, 4223, 4224) branching off the baffle body; and a circuit board electrically connected to the first light emitter and the first light receiver respectively; characterized in that the smoke detector further comprises: a second light emitter disposed in the sensing chamber (4, 5, 6), the second light emitter being located between the first light emitter and the first light receiver and spaced apart from the first light receiver by a central angle of less than 90°, wherein the first baffle is located between the first light emitter and the second light emitter; a second baffle extending from the periphery of the sensing chamber toward the middle portion and disposed between the second light emitter and the first light receiver, wherein the second baffle blocks part of a background light comprising a scattered portion of light emitted by the second light emitter that would otherwise be incident on the first light receiver; and a third baffle disposed at the outer side of the first light receiver, an inner end of the third baffle extending toward the radial direction of the first light receiver. a housing (2, 7); a sensing chamber (4, 5, 6) in the housing, wherein in the sensing chamber, a first light emitter and a first light receiver are disposed at the periphery of the sensing chamber and facing a middle portion of the sensing chamber, the first light emitter and the first light receiver being arranged at a central angle between 90° and 180°; a first baffle in the sensing chamber, the first baffle being disposed adjacent to the first light emitter and including a baffle body and a branch portion, the baffle body extending from the periphery of the sensing chamber toward the middle portion, and the branch portion including a plurality of sub-baffles (4221, 4222, 4223, 4224) branching off the baffle body; and a circuit board electrically connected to the first light emitter and the first light receiver respectively; characterized in that the smoke detector further comprises: a second light emitter disposed in the sensing chamber (4, 5, 6), the second light emitter being located between the first light emitter and the first light receiver and spaced apart from the first light receiver by a central angle of less than 90°, wherein the first baffle is located between the first light emitter and the second light emitter; a second baffle extending from the periphery of the sensing chamber toward the middle portion and disposed between the second light emitter and the first light receiver, wherein the second baffle blocks part of a background light comprising a scattered portion of light emitted by the second light emitter that would otherwise be incident on the first light receiver; and a third baffle disposed at the outer side of the first light receiver, an inner end of the third baffle extending toward the radial direction of the first light receiver. a second light emitter disposed in the sensing chamber (4, 5, 6), the second light emitter being located between the first light emitter and the first light receiver and spaced apart from the first light receiver by a central angle of less than 90°, wherein the first baffle is located between the first light emitter and the second light emitter; a second baffle extending from the periphery of the sensing chamber toward the middle portion and disposed between the second light emitter and the first light receiver, wherein the second baffle blocks part of a background light comprising a scattered portion of light emitted by the second light emitter that would otherwise be incident on the first light receiver; and a third baffle disposed at the outer side of the first light receiver, an inner end of the third baffle extending toward the radial direction of the first light receiver.