A light intensity controller comprises a diaphragm blade and a driving source for driving the diaphragm blade, wherein the diaphragm blade comprises a light-shielding panel-like component and a shaft component welded with the light-shielding panel-like component through a laser beam; the shaft component is made from laser permeable resin; the light-shielding panel-like component is made from laser absorbable resin; and the end of the shaft component welded to the light-shielding panel-like component is provided with a chamfering part.