The station building is a steel frame cuboidal structure located next to the island platform in between the two tracks.

After the ticket gate, a short flight of steps and a ramp leads up to the island platform.

On 15 December 1923, the stretch of track between Yoshimatsu and Miyakonojō which included Kobayashimachi, was designated as part of the Nippō Main Line.

With the privatization of Japanese National Railways (JNR) on 1 April 1987, Kobayashi came under the control of JR Kyushu.

[3][7][8] On 15 March 2015, a new station building was opened, situated between the tracks and adjacent to the island platform.