An underwater automatic starting device includes at least one first hollow housing, a second hollow housing, at least one electrostatic charge sensor, an actuating control circuit and an actuating element. One end of the first housing is provided with at least one first joint and one end of the second housing is provided with at least one second joint such that the first housing can be coupled to the second housing by engaging the first joint with the second joint. The electrostatic charge sensor, the actuating control circuit and the actuating element are all disposed between an interior of the first housing and an interior of the second housing. The electrostatic charge sensor is coupled to the actuating control circuit so as to sense a state whether the surfaces of the first housing and the second housing are in water or out of water without contacting the water such that the actuating control circuit can automatically control the opening or closing of the actuating element. The actuating element can function as illuminating, audible or vibratory force output to construct a versatile device that can be used as an underwater automatic sensing start.一種水下自動啟動裝置，係包括至少一中空之第一殼體及第二殼體、至少一靜電荷感應器、作動控制電路及作動元件，其中，該第一殼體一端設有至少一第一接合部，該第二殼體一端設有至少一第二接合部，以藉該第一接合部及第二接合部對應接合，使該第一殼體及第二殼體接合，該靜電荷感應器、作動控制電路及作動元件皆納置於該第一殼體內部及第二殼體內部之間，且該靜電荷感應器連結該作動控制電路，以不接觸水之方式感測該第一殼體及第二殼體外表入水或未入水之狀態，並使該作動控制電路得以自動控制該作動元件之開啟或關閉，該作動元件可作發光、聲音或振動力輸出功能，以構成一可應用作為水下自動感測啟動之多用途裝置。
