The present invention relates to a structure of a speed reduction device. The main structure comprises a water tank body, a load bearing assembly, a driving device, and a plurality of leakage preventing insulation members, and the carrier assembly is provided with a first transmission wheel, a first transmission member and a a second transmission wheel, a third transmission wheel, a second transmission member, and at least one output shaft. The driving device and the first to third transmission wheels are coupled to the waterwheel body by the carrying assembly to decelerate and transmit the power of the driving device to the output shaft through the first and second transmission members, thereby increasing the body of the waterwheel Torque, and the leakage preventing insulation is placed at the joint surface of the driving device and the load bearing assembly to avoid the risk of the driving device failing due to leakage or short circuit.本新型為有關一種減速裝置之結構，主要結構包括一水車本體、一承載組件、一驅動裝置、複數防漏絕緣件，且該承載組件上設有一第一傳動輪、一第一傳動件、一第二傳動輪、一第三傳動輪、一第二傳動件、及至少一出力軸。藉由承載組件將驅動裝置及第一至第三傳動輪，結合於水車本體上，以透過第一、第二傳動件將驅動裝置之動力減速並傳遞至出力軸處，而增加對水車本體之扭力，並將防漏絕緣件設置於驅動裝置及承載組件的結合面處，以避免驅動裝置因漏電或短路而故障之風險。
