Henry James had a great interest in French Naturalism for more than two decades. In his ambivalent attitude toward naturalistic writing, James, on the one hand, found a clue to the future of novel from the experimental spirit of the Naturalist writers who emphasized the form and style of novel. On the other hand, he rejected their restricted vision of individual and society. This paper studies James`s critical response to the theory and execution of the French Naturalist writers by focusing on how he modifies such naturalistic values as reality, observation, and descriptions into ones which fit his pragmatic taste of art. James`s interest in naturalistic writing bridges the gap between his concern with social manners in his early novels and that with psychological exploration of individuals in his later works.