A secondary battery includes an electrode assembly having a relatively large capacity due to reducing a width of an uncoated portion and increasing a width of a coated portion by improving welding strength through a combination of ultrasonic welding and laser welding, and a manufacturing method thereof. The manufacturing method of the secondary battery includes preparing at least one electrode assembly including an uncoated portion, provisionally welding the uncoated portion by ultrasonic welding, coupling a current collector having an elastic property to the provisionally welded uncoated portion, and welding the uncoated portion and the current collector by laser welding.