A control device included in a plurality of control devices provided to a controlling system, the plurality of control devices being configured of a plurality of control devices of a control system and at least a control device of a standby system, the control device comprising: a selection unit to select, when a failure of at least any of the plurality of control devices is detected, from a selection table in which a plurality of failure patterns indicating a value in binary form, the value in binary form representing whether a failure is present or absent in all of the control devices of the control system and whether a failure is present or absent in all of the control devices of the standby system, and a plurality of pieces of process information indicating a process to be newly executed or no process to be newly executed are associated with each other, process information associated with a failure pattern of the controlling system; and an execution unit to execute, when the selected process information indicates a process, the process indicated by the selected process information, wherein the value in binary form is a value represented as a bit string formed of a plurality of bits, one bit in the bit string indicates a bit value representing a state of one control device, each process information is set in a memory region with a value including the value in binary form indicated by the failure pattern or a value acquired by adding a base address to the value in binary form indicated by the failure pattern taken as a memory address, and the selection unit acquires the process information from the memory region with the value including the value in binary form indicated by the failure pattern or the value acquired by adding the base address to the value in binary form indicated by the failure pattern taken as the memory address. a selection unit to select, when a failure of at least any of the plurality of control devices is detected, from a selection table in which a plurality of failure patterns indicating a value in binary form, the value in binary form representing whether a failure is present or absent in all of the control devices of the control system and whether a failure is present or absent in all of the control devices of the standby system, and a plurality of pieces of process information indicating a process to be newly executed or no process to be newly executed are associated with each other, process information associated with a failure pattern of the controlling system; and an execution unit to execute, when the selected process information indicates a process, the process indicated by the selected process information, wherein the value in binary form is a value represented as a bit string formed of a plurality of bits, one bit in the bit string indicates a bit value representing a state of one control device, each process information is set in a memory region with a value including the value in binary form indicated by the failure pattern or a value acquired by adding a base address to the value in binary form indicated by the failure pattern taken as a memory address, and the selection unit acquires the process information from the memory region with the value including the value in binary form indicated by the failure pattern or the value acquired by adding the base address to the value in binary form indicated by the failure pattern taken as the memory address.