PURPOSE: To provide a small inclined planet roll device with high rigidity by restraining fixing one of two input shafts.

CONSTITUTION: One or more kinds of working rolls 1, back up rolls 2 or reinforced rings 5 are driven. At the time of driving only the reinforce rings 5, for example, when the working rolls 1 and back up rolls 2 are kept in a fixed position, they are revolved by friction and working is possible without giving rotation to a shaft material. In the case the working rolls 1 are driven, the diameter ratio of the pitch circles of the sun gear 9 to a planet gear 10 are decided in a range from the maximum to the minimum of the diameter ratio of the core material to the working roll in the same position of the core material working part 12.