To provide an electroluminescent device in which an element substrate provided with a light-emitting element and a sealing substrate are bonded to each other without causing thermal damage to the light-emitting element and which is formed using an electroluminescent material. A sheet 108 in which layers of at least two different kinds of metals are stacked is formed in a peripheral portion of one or both of the element substrate 102 provided with an EL element 104 and a sealing substrate 106 bonded to the element substrate 102 so as to face each other. Further, the sheet is irradiated with a focused beam, and the irradiation portion of the sheet is heated, whereby at least two kinds of metals are alloyed, and the element substrate and the sealing substrate are bonded to each other by heat generated in the alloying.