A speaker unit for an earphone is provided. The speaker unit for an earphone includes a frame including a first hole in a front thereof and a second hole in a rear thereof; a yoke disposed on the frame and elongated along a front-to-rear direction; a first magnet disposed on one side of the yoke; a first plate disposed on one side of the first magnet; a first diaphragm disposed on one side of the first plate; a second magnet disposed on the other side of the yoke; a second plate disposed on the other side of the second magnet; and a second diaphragm disposed on the other side of the second plate, wherein the first magnet and the second magnet are together in contact with the yoke, and the yoke includes a first passage that connects the first hole and the second hole.