Shibusawa wrote many short stories and novels based on French literature and Japanese classics.

However, the possibilities for a career in that field disappeared with Japan's defeat in the war, and Shibusawa received notably poor scores in the German language, which was widely used in engineering at the time.

In 1950, after working as an editor at the Modern Nihon magazine under Junnosuke Yoshiyuki for two years (one of the authors he edited was Hisao Juran), Shibusawa entered the University of Tokyo's school of French literature, where he enthusiastically embraced the avant-garde movement of surrealism, which started in France after World War I.

Although Shibusawa did graduate from a master's course at the University of Tokyo, he had to abandon plans to become a professor because of tuberculosis, and started his career as a freelance writer instead.

He relocated from Tokyo to the resort town of Kamakura, Kanagawa prefecture in 1946, due to its reputation for having a healthful climate for lung disorders, and continued to live there to his death.

With the death of his father, he faced financial difficulties, and obtained a part-time job at the publishing company Iwanami Shoten, where he met his future wife, Sumiko Yagawa, who was also a translator and author.

He was fined 70,000 yen (slightly less than US$200 at the time); the triviality of the sum greatly outraged him, given the nine years that the trial had taken from his life.