NOVELTY - Fuel cell (10) comprises a stack of an electrolyte electrode assembly (26) and a pair of separators (28). The electrode assembly is sandwiched between the separators. Each separator has a first member (38) and a second member (62) stacked together. At least one of the first member of first separator and the second member of second separator, is plastically deformed to form a joint portion (89a) for hermetically sealing a predetermined overlapping portion of separators.    USE - As a fuel cell e.g. solid oxide fuel cell (SOFC), used in stationary and mobile applications e.g. vehicles.    ADVANTAGE - Predetermined overlapping portions of the separators in the fuel cell, are sealed hermetically. Hence, glassy seal members having heat resistance and flexibility for maintaining the insulating performance and the sealing performance at high temperature, are not required. Therefore, shattering or volatilization of the seal members does not occur. The fuel cell provides improvement in the sealing reliability and durability at the overlapping portions. In addition, no load needs to be applied to the overlapping portions for improving the sealing performance, thus preventing damage/degradation of the separators or electrolyte electrode assemblies. No excessive stress is generated at the overlapping portions. No load mechanism is required for applying the load. Hence, reduction in overall weight and heat capacity of the fuel cell is easily achieved.    DETAILED DESCRIPTION - The joint portion is formed preferably by a crimping process. The joint portion includes a cylindrical portion (39) subjected to the crimping process, and the cylindrical portion is formed around a fuel gas supply unit (36), and protrudes in a stacking direction. The electrolyte electrode assembly contains an electrolyte (20) interposed between an anode (24) and a cathode (22). The fuel cell further comprises an insulating member (87a) interposed between the first member of first separator and the second member of the second separator at the joint portion.    DESCRIPTION OF DRAWING(S) - The figure shows an enlarged cross sectional view of a fuel cell at a position near a fuel gas supply passage.    fuel cell (10)    electrolyte (20)    cathode (22)    anode (24)    electrolyte electrode assembly (26)    separators (28)    fuel gas supply unit (36)    first member of separator (38)    cylindrical portion of joint portion (39)    second member of separator (62)    fuel gas channel (76)    insulating member (87a,87b)    joint portion. (89a)