PURPOSE: To visually recognize the lighting/extinction state of a confirmation lamp provided in a small-sized housing by leading out the light, from the confirmation lamp to the front end face of the housing through a light guide inserted through fine formed in a labyrinth body.

CONSTITUTION: The light from a confirmation lamp arranged in a housing 1 is led out to the front end face of a housing 1 through the light guide inserted through fins 5 provided in a labyrinth body 2. Therefore, the confirmation lamp 3 indicating generation of a smoke detection signal is provided and its lighting/extinction state is visually recognized even if the housing is so small- sized that the confirmation lamp cannot be provided. Since the light guide is inserted through fins 5 of the labyrinth body 2 provided for suppression of an influence of disturbance, characteristics of sensitivity, etc., are not affected.