Disclosed is a coaxial speaker, including a magnetic circuit system, and two sounding units respectively arranged on the upper and lower sides of the magnetic circuit system. The magnetic circuit system includes a bottom plate, a first magnetic unit including a first magnet and a first yoke, and a second magnetic unit including a second magnet, a second yoke, a third magnet, and a fourth magnet. The second yoke includes an annular plate sandwiched between the second and third magnets, and a hollow protrusion extending to a first through hole of the bottom plate. The third magnet covers a second through hole of the annular plate. The fourth magnet is fixed to the third magnet and contained inside the hollow protrusion. The coaxial speaker is simple and compact in structure, reduces the cost, and can also be used as a receiver with a reverse phase silencer.