Abstract: A suction nozzle unit for selectively aspirating dust from flat surfaces and from joints or edges has a connecting suction member, a body part connected with the latter and having two separate air passages provided with different cross-sections and forming a joint nozzle and a surface nozzle, and a switching element alternatingly communicating each of the passages with the connecting suction member to actuate a respective one of the nozzles. The connecting suction member is rotatably connected with the body part, and the surface nozzle is provided with a bristle-containing member.