A process allocation control method is provided that controls, in a system including an in-vehicle computer mounted in the vehicle and an external computer provided external to the vehicle as nodes communicable with each other, allocation of a process related to driving assistance of the vehicle to the nodes. The process allocation control method includes: estimating an allocation risk of the process being interrupted in cases of allocating the process to either of the nodes, based on at least one of a remaining battery charge of the vehicle or a communication status between the nodes; and determining the node to which the process should be allocated, based on the allocation risk.