The invention discloses a spherical buoy electricity-generating device which comprises a spherical buoy. A transverse shaft supporting base is arranged in the buoy. A swing ball transverse shaft arranged on the transverse shaft supporting base is perpendicular to and fixedly connected with a swing ball vertical shaft. The upper end of the swing ball vertical shaft is fixedly connected with a swing ball playing a balancing role. The lower end of the swing ball vertical shaft is fixedly connected to the bottom of the buoy through two traction springs. One end of the swing ball transverse shaft is connected with the driving end of an overrun clutch, the driven end of the overrun clutch is connected with the rotor input end of an electricity generator, the stator electricity output end of the electricity generator is connected with a charging chip used for charging, and the output end of the charging chip is connected with a storage battery through two wires II. According to the spherical buoy electricity-generating device, thrust of waves can be utilized for generating electricity automatically so as to charge the storage battery inside the buoy, so that electricity is supplied to an electric instrument inside the buoy, the structure is simple and is not limited by the external environment, and it can be ensured that the electric instrument inside the buoy always has the sufficient electric quantity.