A differential mode signal transmission module includes a first section having an external connection end on which at least a pair of differential mode signal transmission terminals are formed and includes a grounding terminal, a first differential mode signal terminal, and a second differential mode signal terminal. The extension connection end of the first section forms a counterpart signal terminals corresponding to those of the external connection end. At least one first conductive connection line is formed on the first section. The conductive connection line connects the grounding terminal of the external connection end of the first section to a collective grounding point. The extension connection end of the first section is connected to an extension section. The extension section is further connected to a second section opposite to the first section. The extension section includes at least one slit line in order to form a bundled section. The first section, the second section, and the extension section include at least one fold line.