The quasi-seven-month oscillation (QSO) found in the atmospheric relative angular momentums and the length of day is analyzed in detail by using the Japan Meteorological Agency data. The major source of the QSO is the equatorial tropospheric zonal winds, in particular between the equator and 15°S. However, it seems to have been disturbed or masked by some effects of the ENSOs, behaving as an ENSO-connected intermittent oscillation. Its large amplitude, amounting to one third of that in the stratospheric QBO, results from its phase independency of height. Probably disparate from the QSO, exists the eight-to-nine-month oscillation in the equatorial troposphere stationarily through all the data periods, including the El Niño periods.