Redundant power supply device

A redundant power supply device, particularly the one without installing a heat dissipating fan, includes a chassis (10) having at least one power input accommodating space (11) and a plurality of power output accommodating spaces (12), a back panel device (20) comprising a back panel (21), which is a printed circuit board mounted onto the chassis (10), a plurality of power supply devices (40) installed in the power output accommodating spaces (12) and electrically connected to the back panel (21), at least one power input module (30) inserted into the power input accommodating space (11) for providing an external AC-to-DC or DC-to-DC conversion and electrically coupling the back panel (21). During an application without changing the back panel (21), the power input accommodating space (11) is disposed opposite to the external input power supply, and the power input includes at least one power input module (30) with AC-to-DC or DC-to-DC conversion to achieve high interchangeability, economic benefit and product competitiveness.