This method of manufacturing an electrode assembly comprising electrodes that include a tab involves: a step for preparing a tab laminate comprising laminated tabs, and a step in which, by irradiating an energy beam onto an end surface of the tab laminate which extends in the direction of lamination of the tab laminate, a welded portion is formed to the inside from the end surface of the tab laminate. In the step for forming the welded portion, an energy beam is scanned on the end surface of the tab laminate along a direction intersecting with the direction of lamination of the tab laminate.
