This article describes first of all the distinction between analytic judgement and synthetic judgement in the philosophy of Kant and the meanings of this distinction with regards to metaphysics. Secondly, I describe the critiques of this distinction by Ayer and Quine. Ayer maintains that Kant uses two different criteria in making this distinction, therefore Kant's view is not tenable. Subsequently, Ayer denies the validity of metaphysical knowledge. Quine maintains that since we are not able to fully elucidate ”analyticality,” therefore, we cannot clearly distinguish the boundaries between analytic judgement and synthetic judgement. Finally, I point oat the reasons why the critiques by Ayer and Quine are not sufficient, and thereby one cannot deny this distinction.