Provided is a method for manufacturing a sealed battery, capable of reducing an erroneous determination rate in a leak testing step. The method including the leak testing step for detecting leak of a detection gas introduced into a battery case, includes: an introducing step for introducing the detection gas into the battery case which is temporarily sealed by covering the battery case; and an adjusting step for adjusting at least one of the pressure inside the battery case temporarily sealed and the pressure outside the battery case so that the pressure inside the battery case into which the detection gas has been introduced is lower than the pressure outside the battery case.