There is provided a communication delay time derivation method for calculating a communication delay time depending on a combination of channels set between communication terminals on a communication path in the MCH/IF environment. When selecting a channel to be used for communication in each section on the communication path per section between communication terminals on the communication path, a calculation target section specification means 82 detects an inter-terminal selected channel repetitive pattern as a pattern of the selected channels cyclically appearing on the communication path, and defines a section corresponding to the inter-terminal selected channel repetitive pattern as a communication delay time calculation target section. A communication delay time derivation means 83 derives a communication delay time in the calculation target section based on the inter-terminal selected channel repetitive pattern.