To provide a "diaphragm unit" with high strength and high radiation effect without especially enlarging the thickness, and to provide a "speaker device" using the unit.

The diaphragm unit 10 where a planar voice coil 13 to become a spiral wiring pattern is formed on the front surface of a flexible base material 11 includes: an outer terminal 15 continuously formed from the outer wiring end 132 of the spiral wiring pattern 13; and an extension part 14 which is continuously formed from the inner wiring end 133 of the spiral wiring pattern 13 and has an area larger than that of the outer terminal 15. The speaker device includes the above diaphragm unit 10 and a magnetic circuit 20.