Abstract: A magnetic circuit switching device with single-sided attraction includes a housing with a first side and a second side individually arranged at either side, where the first side has an attraction surface to attract an iron core; a permanent magnet having a first type magnetic pole and a second type magnetic pole individually arranged at inner and outer side with opposite properties; a nonconductive axial tube for the iron core to engage, having an opening at the right side extending to the second side of the housing; and a spring providing elastic force for the iron core to displace. With a magnetic path alteration function and the elastic force from the spring, the structure is able to keep the iron core in a pre-determined position. Therefore the iron core has a wider stretching range for operation, increasing the possibilities of wider application and ensuring in-time adjusting in case of deviation and wear and tear of the device.