more than 7-times than the average values reported by previous surveys. It is the same trend with the sample of G.P. Smith et al. (2002), which indicates that the numbers and sky distributions of EROs are very different in each field of view. Those are also consistent with the results by other wide field ERO surveys, which suggest the clustering properties of EROs (Daddi et al. 2001; Thompson et al. 1999). The most different property of our sample from G.P. Smith et al.(2002)’s is that most EROs identified in MS $0451.6-0305$ show the colors which are common in dusty star-forming galaxies at high redshift(Figure 7), which indicate their strong star-formation activities, while most EROs are passively evolved objects in Smith et al.’s. Daddi et al.(2002) suggested that the strength of clustering is stronger in the old ERO population than that of dusty starburst EROs, and our results on the MS $0451.6-0305$ may be a very rare case. It may indicate that the deeper is the depth of observation, for example down to $K'=20.5$, the more will the ratio of dusty starbursts in ERO population increase. This is suggested by Smail et al. (2002b) with a radio-selected ERO sample, and the 