To know the level of light pollution due to human activities, we performed sky brightness measurements at Bosscha Observatory, Indonesia (107$^\circ$36’ E; 6$^\circ$49’ S, 1300 m above the sea level) during years 2011-2012 by using a portable photometer at zenith direction. From 400 records of night, we obtained that average and maximum sky brightness were 17.75 $\pm$ 0.86 mag/arcsec sq. and 19.14 $\pm$ 0.79 mag/arcsec sq., respectively. Cities around the Observatory, that are Bandung and Lembang, clearly give a strong contribution to light pollution. The patches of Milky Way galaxy are disappearing from the sky. Higher maximum sky brightness occurred after midnight. Brightness values before midnight were 17.83 $\pm$ 0.83 mag/arcsec sq. on average and 18.98 $\pm$ 0.78 mag/arcsec sq. at maximum, with average temperature of 18.8 $\pm$ 1.3 $^\circ$C. The average and maximum magnitudes after midnight were 17.67 $\pm$ 0.88 mag/arcsec sq. and 19.41 $\pm$ 1.24 mag/arcsec sq. with average temperature of 17.1 $\pm$ 1.6 $^\circ$C. Sky brightness depends on Moon age and monthly seasonal variations, but it has no relation with Earth eccentricity.