FIG. 27 is a view illustrating a state that the power reception coupler 320 of FIG. 24 is rotated 90 degrees counterclockwise. In the embodiment of FIG. 24, since the through holes 311b, 321b are formed axially symmetrically, electric fields formed by the power transmission coupler 310 and the power reception coupler 320 become axially symmetrical similarly to FIG. 13 and FIG. 14. Thus, when the power reception coupler 320 is rotated as illustrated in FIG. 27, changes in characteristics hardly occur. More particularly, FIG. 28 illustrates frequency characteristics of transmission efficiency η21 and reflection loss η11 of the embodiment illustrated in FIG. 27, and FIG. 29 is a smith chart of input impedance S11. From comparison of these diagrams with FIG. 25 and FIG. 26, changes in characteristics hardly occur even when the power reception coupler 320 is rotated. Of course, the same is true in the case where the power transmission coupler 310 is rotated. Note that in the example of FIG. 24, the through holes are provided in both the center electrodes 311, 321, but they may be provided in at least one of them. Further, cutouts may be provided as necessary in at least one of the center electrodes 311, 321 and the annular electrodes 312, 322 as described above.