An electrical power-generating device comprising an outer shell, at least one power generation unit, a centerboard, a transmission axis, a gear set and a starting device. The major characteristic is: at least one power generation unit and at least one centerboard are installed vertically to the transmission axis. The centerboards with many permanent magnetic bodies are inside the power generation unit, many coil sets are installed on both sides of the power generation unit, the number of the permanent magnetic bodies is equal or twice the number of the coil sets; users can roll the starting device and turn the transmission axis, the movement generates electrical power when the permanent magnet bodies pass through the coil sets on both sides.