NOVELTY - The device has a vertical well (1) whose upper side is horizontally provided with a transmission shaft (4). A bottom part of the vertical well is provided with a lower transmission shaft. Upper and lower chain wheels are wound with chains. The chains are connected with a high pressure air pocket (17), where a lower side of the high pressure air pocket is provided with a balance weight (19). The transmission shaft is connected with a generator (7) through a speed increaser (6). An external periphery of a cushion device seat is provided with non-magnetic stainless steel materials.    USE - Electric power generating device.    ADVANTAGE - The device utilizes the gravitational attraction and the buoyancy force of liquid as the energy sources, and makes the air pocket to rise and fall through the air charging and the air discharging of the air pocket, so that the transmission shaft is driven to generate the electric power. The device only needs to input initial start energy. Other energy sources are not needed as the generator of the device when the device is started. The generator generates the electric power through natural sources, so that the device has energy economization and non pollution. The device is not affected by the factors such as geographic locations, seasons, and climates.    DETAILED DESCRIPTION - The balance weight is provided with shell bodies and pipelines made of non magnetic conductive stainless steel materials, where a housing of the balance weight is made of stainless steel materials while an internal part is filled with heavy metals. The cushion device seat is provided with an internal wall made of magnetic stainless steel materials. The balance weight is equipped with a circular trumpet shape interface made of magnetic conductive stainless steel materials.    DESCRIPTION OF DRAWING(S) - The drawing shows a side view of an electric power generating device.    Vertical well (1)    Transmission shaft (4)    Speed increaser (6)    Generator (7)    High pressure air pocket (17)    Balance weight (19)