A speaker unit includes a magnet having poles and generating magnetic flux, and a yoke part forming a path of the magnetic flux and including a first yoke extending from one of the poles, a second yoke extending from another one of the poles, and magnetic gaps disposed between the first yoke and the second yoke. The speaker unit further includes a voice coil disposed between the magnetic gaps and moving when applied with an electric current, and a diaphragm generating sound pressure while vibrating according to the movement of the voice coil. The first yoke includes magnetic plates protruding toward the second yoke, and the magnetic plates have thicknesses different from each other.