  An extensive photometric monitoring of KH 15D, an enigmatic variable in the
young star cluster NGC 2264, has been conducted. Simultaneous and accurate
near-infrared (JHKs-bands) photometry is presented between 2003 December and
2005 March covering most of the variable phase. The infrared variability is
characterized by large-amplitude and long-lasting eclipse, as observed at
optical. The period of variability is 48.3 +/- 0.2 days, the maximum
photometric amplitude of variability is ~4.2 mag, and the eclipse duration is
\~0.5 in phase units. These are consistent with the most recent period,
amplitude, and duration at optical. The blueing of the J-H color (~0.16 mag)
during the eclipse, which has been suggested before, is unambiguously
confirmed; a similar blueing at H-Ks is less clear but is probably present at a
similar level. The overall shape of the JHKs light curves is very similar to
the optical one, including a fair time-symmetry and a less stable flux during
the eclipse with a slight hump near the zero phase. Most of these variability
features of KH 15D observed at near-infrared wavelengths can be explained with
the recent model employing an eclipse by the inclined, precessing disk and an
outer scattering region around a pre-main-sequence binary.
