PURPOSE: To prevent a rotating magnetic disk from flopping and to perform stable high-precision and high-density recording by providing main magnetic supports which have a concave curved surface and a guide plate which has a convex curved surface, arranging both curved surface oppositely with the recording medium between, and arranging a main magnetic pole in the opposition space.

CONSTITUTION: The main magnetic pole 24 made of a thin film with high magnetic permeability is sandwiched between nonmagnetic bases 25, which have a front and a rear flat part 27 and 28 nearly in parallel to the rotating disk 21 and also have the concave curved surface between both flat parts; and the main magnetic pole 24 is arranged in the curved surface. The guide plate 26, on the other hand, is made of nonmagnetic or high-magnetic permeability material; and the convex curved surface 30 is formed facing the tip part 29 of the main magnetic pole and the concave curved surface of the supports 25, and a front and a rear flat parts 31 and 32 are also formed facing the front and rear flat parts 27 and 28 of the support.