To prevent a coating layer from being mixed with air bubbles, and to enhance an optical transmission characteristic and reliability under high water pressure of a submarine optical fiber cable.

Plural optical fibers 6 are fed into a resin inside a coating die 16 to be passed through, while twisting them together in a periphery of a strength member 1, to coat periphries of the fibers 6 with the resin, in this manufacturing method for an optical fiber unit 17. The die 16 is rotated in a direction same to a twisting direction of the optical fibers 6. The optical fibers 6 are wound in optical fiber feed bobbins 5, the bobbins 5 are provided inside an optical fiber twisting machine 7 rotating around the strength member 1, and the die 16 is rotated at the rotational speed substantially the same as that of the twisting machine 7.