According to one embodiment, a luminaire includes a main body (10), a light-emitting element (32), and a cover (40). The main body includes a top plate section (11) having a rectangular plate shape and a pair of side plate sections (12) provided to project to the top plate section and extending in the longitudinal direction of the top plate section. The light-emitting element is provided, in each of the side plate sections, on a side surface (14) on the opposite side of the other side plate section. The cover is attached to the side plate section to project to the outer side of the side surface and configured to cover the light-emitting element and have transparency to light emitted from the light-emitting element.