  The results of near-infrared photometric observations of a transit event of
an extrasolar planet HAT-P-54b are presented herein. Precise near-infrared
photometry was carried out using the Nayuta 2 m telescope at Nishi-Harima
Astronomical Observatory, Japan and Nishi-harima Infrared Camera (NIC). 170 J-,
H-, and Ks-band images were taken in each band in 196 minutes. The flux of the
planetary system was observed to decrease during the transit event. While the
the Ks-band transit depth is similar to that in the r-band, the J- and H-band
transits are deeper than those in the Ks-band. We constructed simple models of
the planetary atmosphere and found that the observed transit depths are well
reproduced by inflated atmosphere containing H2S molecule.
