K-band differential number counts for field galaxies and EROs in COSMOS, compared with a compilation of results taken from various sources. The filled squares correspond to field galaxies, and triangles correspond to EROs. Red, green, and blue color correspond to the counts of galaxies and EROs in the COSMOS (this paper), Daddi-F and Deep3a-F (Kong et al. 2006), respectively. The error bars of EROs indicate the Poissonian uncertainties.