Kōshū Kaidō
Keio sets about a bus enterprise in early stages of Shōwa period again. Banzai Jidōsha Co.() which operated around the bus from the end of Taishō period changed the company name to the Kōshū Kaidō Noriai Jidōsha Co.() in July, 1924, and the route was extended to Tama-mura Tokyo city-owned park cemetery (present Tama Cemetery) through Karasuyama and Chofu. However, Keio which has a railroad in parallel to the Kōshū Kaidō felt this as the threat, and made more than the majority of the holdings of the company acquisition and an associated company in May, 1927. Furthermore, the Keio acquired Kōshū Kaidō Noriai Jidōsha in 1937, and absorbed enterprise all. Thereby, the automobile division and Sasazuka office were installed and the bus enterprise of the direct management which leads to the present Keio Dentetsu Bus Group was resumed. Hachiōji Shigai Jidōsha Co.() was purchased and the Hachioji Office was established in 1938. Moreover, Takahata Noriai () is purchased in the same year, Yugi Noriai Jidōsha () was purchased in 1939, and these enterprises were absorbed. The Pacific War broke out and the route within Yamanote Line was transferred to Tokyo City on February 1, 1942 for the war integration based on a land transport business method of preparation. Moreover, the Keio came to be merged by Tokyu Corporation on May 31, 1944 (Keio Teito Electric Railway dissociated from Tokyu in 1948).