A diagram creating device comprising: a database which includes a track section master which stores names of a plurality of track sections in a railroad network including the plurality of track sections, and track section codes for identifying the names as track section data, a station order master which stores a relationship between a station order code which, together with the track section codes, indicates an order from a reference station in the same track section, station names and kilometers from the reference station as train order data, and a junction master which stores a relationship between the track section codes related to a junction station belonging to the plurality of track sections, the station order code and a junction destination track section code as junction data; a processing device which reads track section data, the station order data and the junction data from the database, and creates a diagram which displays a station line and a diagram line associated with the station name, on a two-dimensional plane formed by a time axis and a distance axis; and a display device which displays the created diagram, wherein the processing device includes a diagram display processing unit which displays the names of the track sections and the station names of each station included in the track sections, and the station line which displays the distances of each station from a reference point, in parallel to the time axis in the diagram, wherein said diagram display processing unit displays a diagram creation screen including a diagram with junction buttons associated with junction destination track section codes and junction track section directions, near the station line associated with the junction station in the diagram based on junction data, and a track section switch unit which, when the junction button is pushed on the diagram creation screen, reads the station order data and the junction data based on the track section code of the junction destination, switches part of the station line related to the track section displayed in the diagram, to the station line subsequent to the junction station belonging to the another track section with the junction station as a starting point, wherein said track section switch unit switches a track section by outputting to the diagram display processing unit junction destination track section codes, station order codes and junction destination track section directions associated with the junction buttons upon creation of the diagram, and causes the diagram display processing unit to re-read master data, and displays the station line. a database which includes a track section master which stores names of a plurality of track sections in a railroad network including the plurality of track sections, and track section codes for identifying the names as track section data, a station order master which stores a relationship between a station order code which, together with the track section codes, indicates an order from a reference station in the same track section, station names and kilometers from the reference station as train order data, and a junction master which stores a relationship between the track section codes related to a junction station belonging to the plurality of track sections, the station order code and a junction destination track section code as junction data; a processing device which reads track section data, the station order data and the junction data from the database, and creates a diagram which displays a station line and a diagram line associated with the station name, on a two-dimensional plane formed by a time axis and a distance axis; and a display device which displays the created diagram, wherein the processing device includes a diagram display processing unit which displays the names of the track sections and the station names of each station included in the track sections, and the station line which displays the distances of each station from a reference point, in parallel to the time axis in the diagram, wherein said diagram display processing unit displays a diagram creation screen including a diagram with junction buttons associated with junction destination track section codes and junction track section directions, near the station line associated with the junction station in the diagram based on junction data, and a track section switch unit which, when the junction button is pushed on the diagram creation screen, reads the station order data and the junction data based on the track section code of the junction destination, switches part of the station line related to the track section displayed in the diagram, to the station line subsequent to the junction station belonging to the another track section with the junction station as a starting point, wherein said track section switch unit switches a track section by outputting to the diagram display processing unit junction destination track section codes, station order codes and junction destination track section directions associated with the junction buttons upon creation of the diagram, and causes the diagram display processing unit to re-read master data, and displays the station line.