NOVELTY - The by-product elimination device has a fuel pack (20A), a power generation module (10A) and an absorbent charged portion which selectively absorbs carbon dioxide contained in gas (I) fed from reforming portion and feeds gas (II) whose carbon dioxide concentration is lowered by gas (I), to the fuel cell.    USE - For a portable device to which a removable general-purpose cell is applied as a power supply, such as a mobile phone, personal digital assistant, notebook-size personal computer, digital video camera and digital still camera, or display unit such as liquid crystal element and electroluminescent element.    ADVANTAGE - The by-product elimination device provides sufficient power consistency and energy utilization efficiency at an easy rate without exhaust of by-product to the environment. The by-products that are formed until power generation are accommodated, hence the effect on environment during power generation is controlled, and hydrogen with high concentration is supplied to the fuel cell, thereby performing power generation effectively. Since drive of power generation portion is controlled, waste of power generation fuel is suppressed and energy resource utilization efficiency is improved.    DETAILED DESCRIPTION - The by-product elimination device has a fuel pack (20A), a power generation module (10A) and an absorbent charged portion which selectively absorbs carbon dioxide contained in gas (I) fed from reforming portion and feeds gas (II) whose carbon dioxide concentration is lowered by gas (I), to the fuel cell. The fuel pack is provided with a fuel charged portion having a power generation fuel having a liquid or gas containing hydrogen, charged. The module can be attached to or detached from the fuel pack. The module has a reforming portion which transforms the power generation fuel supplied from the fuel charged portion into gas (I) containing hydrogen and carbon dioxide as main components, and a fuel cell which generates an electrical energy by using hydrogen gas contained in gas (I). An INDEPENDENT CLAIM is included for a fuel pack which can be connected to a power generation module without restraint.    DESCRIPTION OF DRAWING(S) - The figure shows a block diagram of a power generation module applied to the power supply system.    Power generation module (10A)    Fuel pack (20A)