In Japanese film history, the late 1930s is known as a period when interest in filmic “realism” rose. This study examines how this interest in filmic realism influenced musical accompaniment in narrative films in the late 1930s. It mainly focuses on two complementary aspects of filmic realism: one based on naturalist/socialist realism in literature and the other, based on a new conception of filmic representation that emphasized audiovisual realism. This study investigates the contrasting influences of these two aspects. One of their influences was the decrease in the use of non-diegetic music, a practice reported in contemporary texts and confirmed by existing realist films. The first half of the paper presents an analysis of the contemporary discourse on filmic realism and the arguments for the exclusion of non-diegetic music, and reveals that musical accompaniment was considered unsuitable for both aspects of realism. However, their influences were not restricted to the exclusion of non-diegetic music. Musical accompaniment was not completely abandoned, and some contemporary Japanese film composers sought an effective way of using it in realist films. The latter half of this paper shows the efforts of Fukai Shiro, one such leading Japanese composer, in this regard.