A rolling motion based power generation device can be arranged in rolling type wave power generation equipment or rolling type wave absorption dykes, and belongs to the field of ocean power generation new energy. The power generation device includes a first rotation shaft, a first one-way bearing, a big gear, a small gear, a second rotation shaft, a power generator, bearings, a second one-way bearing, and a rolling device; the first rotation shaft and the rolling device are fixedly connected; the first one-way bearing fixedly sleeves the first rotation shaft; the big gear fixedly sleeves the first one-way bearing; the power generator and the bearings are fixedly connected to the rolling device; the second rotation shaft is connected to the power generator and the bearings; the second one-way bearing fixedly sleeves the second rotation shaft; and the small gear fixedly sleeves the second one-way bearing, is positioned between the power generator and the bearings, and is tightly engaged with the big gear. The power generation device is simple in structure, is low in cost, is high in performance ratio, is high in reliability, can avoid pollution, can generate power in regular waves or irregular waves, and has excellent wave absorbing ability.