This invention provides a manufacturing method of an MEA in which electrode catalyst layers adhere sufficiently to a polymer electrolyte membrane and the fringe area of the polymer electrolyte membrane has no large waviness to cause a gas seal problem when used in a fuel cell. The controller preferably has an eta control circuit responsive to the feedback. The insulating material core has opposed first and second surfaces, a pair of spaced-apart longitudinal edges, and a pair of spaced-apart lateral edges extending between the pair of longitudinal edges.