An aging apparatus has a roller group consisting of a front roller, a middle roller and a rear roller, and a table for supporting the roller group. The middle roller takes a press state pressing a flexible tube with a constant force and a retraction state staying away from the flexible tube. In aging operation, while the middle roller comes in the press state, the table moves from a start position being a farthest end of the flexible tube to an end position. After the aging operation, the middle roller comes in the retraction state and the table returns to the start position. The aging operation is performed a predetermined number of times on the same flexible tube, so that the flexible tube is bent more largely with increase in the number of execution.
