Ionospheric three-dimensional currents caused by semidiurnal tidal winds are examined by a magnetic field line coordinate system, assuming infinite parallel conductivity. Electrostatic potential generated by (2,2) tidal mode is mainly distributed in the low-latitude region, compared with that by (2,4) mode. Height integrated currents obtained by using the authors' assumed wind field are too strong and not similar to a normal Sq current system, unlike that of (1,-2) mode. Therefore these currents do not seem to flow normally, but their structure resembles that of equatorial counterelectrojet in the afternoon, and their variation may be one of the causes of day-to-day changes in Sq currents.