To enable multi-layer application with excellent film thickness and production of a high-density recording type magnetic tape.

This method uses a multi-layer extrusion type coator and carries out formation of two coating films by simultaneous coating on a support 1. In the tip part of the die head of the applicator, a front lip 2a, a slit 2b for discharge of a lower layer coating material, a middle lip 2c, a slit 2d for discharge of an upper layer coating material and back lip 2e are disposed in order from the upstream side in the moving direction of the support. When the viscosity of a lower coating film on coating is 3×10-2 to 10×10-2 Pas, the film thickness of the lower coating film in a dry state is 0.7-2.1 μm, the film-forming rate is 50-350 m/min and the film thickness of an upper coating film in a dry state is ≤0.05 μm, the width L of the slit 2d of the head 2 is adjusted to 60 μm or less.