The present invention relates to a flat-type slim speaker, specifically, to a rectangular flat-type slim speaker having an integrated yoke enabling a slim magnetic core. The present invention comprises: a voice coil plate which comprises a voice coil vertically erected; magnets separated with the voice coil plate therebetween; a diaphragm coming into contact with an upper end surface of the voice coil plate and having an edge part which adheres to a seating part of the upper end of a yoke; a damper which is connected to a damper attachment part of the lower end surface of the voice coil plate and adheres to the lower end of the yoke; and the yoke having a slit into which the voice coil plate can be inserted in a longitudinal direction at the center thereof, and a space into which the magnets can be inserted from side to side.