An adhesion method including: a step (1), disposing a stickable-curable adhesive layer on a first adherend; a step (2), disposing a curing agent layer on a second adherend, the curing agent layer being able to cure the stickable-curable adhesive layer by contacting and reacting with the stickable-curable adhesive layer; and a step (3), bringing the stickable-curable adhesive layer into contact with the curing agent layer so that they are sandwiched by the first adherend and the second adherend.