In Marshall's work, the evolutionism is one of the most important components of his system of thought. This view was formed in his psychological study, which was the earliest one in his academic life. His conclusion is that, in the psychological aspect of man, mental action consists of self-consciousness plus mechanical agents; the existence of self-consciousness is an unknowable phenomenon by human experience, but the forms of self-consciousness have evolutioned in correlation with the evolution of mechanical agents. We find especially in this paper, the following three points. First, Marshall's view of evolutionism is very closely like that of H. Spencer, who established his system of philosophy and science in Victorian England. Secondly, in expressing his view on it Marshall attacked the philosophy of consciousness, which maintained that self-consciousness is forever. Thirdly, Marshall came to distinguish self-consciousness from soul through the reading of J. Grote's work ‘Exploratio Philosophica’ (1865).