The company's earliest predecessor was the founded in 1905. In 1906 the company was reorganized as the , and in 1910 was renamed yet again to . It began operating its first stretch of railway between Sasazuka and Chōfu in 1913. By 1923, Keiō had completed its main railway line (now the Keiō Line) between Shinjuku and Hachiōji. Track along the Fuchū – Hachiōji section was originally laid in 1,067 mm gauge by the ; it was later changed to match the rest of the line's 1,372 mm gauge.