This tunnel excavation method is provided with: a step (first excavation step) in which an excavation machine (10) for performing excavation in a state in which grippers (12a) thereof press against tunnel side walls is used to excavate 3 first tunnels (T1) which are substantially parallel to each other; and a step (second excavation step) in which second tunnels (T2) which intersect the first tunnels (T1) are excavated.