A circuit-design support method includes obtaining information for a circuit having a logic circuit in which signal lines are connected to input terminals, signals of the signal lines being output via the logic circuit; obtaining information concerning a control circuit that has a first flip-flop for scanning and that can control a value of a given signal line by a value set by the first flip-flop; selecting, based on the circuit information, a second flip-flop at an output destination of a signal from the logic circuit, among second flip-flops of the circuit; and generating, based on the control circuit information, information indicating a serial connection of the control circuit between an output source of the signal of the given signal line and the given signal line and a connection of a data input terminal of the first flip-flop and an output terminal of the selected second flip-flop.