An electronic control device includes: a first input-output terminal and a second input-output terminal through which differential signals are input and output; a transceiver integrated circuit (IC) that transmits and receives the differential signals; a first line that connects the first input-output terminal and the transceiver IC; and a second line that connects the second input-output terminal and the transceiver IC. A first capacitance that is a capacitance between the first line and a ground is at least 80 pF and at most 220 pF, and a second capacitance that is a capacitance between the second line and the ground is at least 80 pF and at most 220 pF.