Provided is a speaker box, including housing and sounding unit having diaphragm including vibration portion and suspension portion. The housing includes holder, lower and upper covers. The holder includes holder body, holder extension portion and holder fixing portion. The sounding unit is fixed to the holder fixing portion. Orthographic projection of the vibration portion completely falls into the holder body. The suspension portion is arc-shaped formed by recessing away from the holder body. The lower cover includes lower cover plate and lower cover sidewall. The sounding unit, the holder and the lower cover sidewall define front sound cavity. The sounding unit and the lower cover define rear sound cavity. The lower cover sidewall, the holder fixing portion, the holder extension portion and the upper cover define auxiliary rear sound cavity communicated with the rear sound cavity. The speaker box has large cavity volume and good acoustic performance.