NOVELTY - The method involves winding a fiber (fb) around a mandrel (20) of a tank container form by utilizing a fiber winding apparatus (S110). A chuck part (430) is moved along X-direction (S115). The fiber is fixed between an existing part and the fiber winding apparatus. The fiber fixed between the existing part and the fiber winding apparatus is disconnected (S130). The fiber is drawn-out from a helical winding apparatus (200). The fiber winding apparatus is arranged such that an outer periphery of the mandrel is enclosed. The fiber is made of thermosetting resin.    USE - Method for manufacturing a high pressure gas tank i.e. hydrogen gas accommodation tank, that is utilized for storing hydrogen gas i.e. fuel gas, in a fuel cell system and a fuel cell vehicle. Can also be used for storing liquid.    ADVANTAGE - The method enables disconnecting the fiber that is fixed between the existing part and the fiber winding apparatus, so that producibility of a tank can be improved, operativity of the apparatus of the tank can be improved, power can be saved, manufacture facilitation of the tank can be improved, shift of the fiber can be prevented, breadth of the fiber after disconnection can be suppressed and quality degradation of the tank can be suppressed. The cost of the tank can be reduced.    DETAILED DESCRIPTION - The fiber is a carbon fiber such as polyacrylonitrile (PAN)-type carbon fiber and polyacrylonitrile (PAN)-type carbon fiber, and prepregs such as rayon-type carbon fiber and pitch-type carbon fiber. The mandrel is made of resin molded product and metal materials such as highly strong aluminum material and stainless steel material. An INDEPENDENT CLAIM is also included for a fiber winding apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a process flow diagram illustrating a manufacturing process of a tank.    Step for winding a fiber around a mandrel of a tank container form by utilizing a fiber winding apparatus (S110)    Step for moving a chuck part along X-direction (S115)    Step for disconnecting fiber fixed between an existing part and a fiber winding apparatus (S130)    Fiber (fb)    Mandrel (20)    Helical winding apparatus (200)    Chuck part (430)