The utility model relates to an iron foreign body extractor in an oil-immersed transformer oil tank and belongs to the technical field of electronic detection equipment. According to the technical scheme, the iron foreign body extractor comprises the transformer oil tank (1), transformer oil (2), two insulating plate wheels (3), an annular magnet (4), a rotation shaft (5), a telescopic insulating rod (6) and a metal foreign body (7), wherein the annular magnet (4) is arranged between the two insulating plate wheels (3) to form an extractor main body; the telescopic insulating rod (6) is mutually connected with the extractor main body by virtue of the rotation shaft (5); the insulating plate wheels (3) are circular. The iron foreign body extractor has the beneficial effects as follows: the blackout time needed by maintenance is greatly shortened, manpower and material resources are saved, the maintenance cost is reduced, a complex problem is simplified, the production cost is low, and cost minimization and value maximization are really realized. The operation is easily understood, and the practicality is high.