  We present the observation of a charge-sign dependent solar modulation of
galactic cosmic rays (GCRs) with the CALorimetric Electron Telescope onboard
the International Space Station over 6 yr, corresponding to the positive
polarity of the solar magnetic field. The observed variation of proton count
rate is consistent with the neutron monitor count rate, validating our methods
for determining the proton count rate. It is observed by the CALorimetric
Electron Telescope that both GCR electron and proton count rates at the same
average rigidity vary in anticorrelation with the tilt angle of the
heliospheric current sheet, while the amplitude of the variation is
significantly larger in the electron count rate than in the proton count rate.
We show that this observed charge-sign dependence is reproduced by a numerical
``drift model'' of the GCR transport in the heliosphere. This is a clear
signature of the drift effect on the long-term solar modulation observed with a
single detector.
