An underscreen biometrics authentication device, a biometrics authentication unit, and a terminal device are provided. The underscreen biometrics authentication device includes a display screen and a biometrics authentication module, the biometrics authentication module is fixedly installed below the display screen, and between the biometrics authentication module and the display screen. There is a gap. In the embodiment of the present application, by designing the biometrics authentication module and the lower surface of the display screen separately, it is possible to reduce the difficulty of removing the biometrics authentication module and improve the maintainability of the terminal device. You can Further, the complexity in producing the underscreen biometrics authentication module is reduced, the yield is improved, and the production cost is further reduced. [Selection diagram] Figure 1
