  We study the clustering properties of about 1200 z~4 Lyman Break Galaxy (LBG)
candidates with i'<26 which are selected by color from deep BRi' imaging data
of a 618 arcmin^2 area in the Subaru/XMM-Newton Deep Field taken with Subaru
Prime Focus Camera. The contamination and completeness of our LBG sample are
evaluated, on the basis of the Hubble Deep Field North (HDFN) objects, to be
17% and 45%, respectively. We derive the angular correlation function over
theta = 2''-1000'', and find that it is fitted fairly well by a power law,
omega(theta)=A_omega theta^{-0.8}, with A_omega = 0.71 +/- 0.26. We then
calculate the correlation length r0 (in comoving units) of the two-point
spatial correlation function xi(r) = (r/r0)^{-1.8} from A_omega using the
redshift distribution of LBGs derived from the HDFN, and find r0=2.7
(+0.5/-0.6) h^{-1} Mpc in a Lambda-dominated universe (Omega_m=0.3 and
Omega_Lambda=0.7). This is twice larger than the correlation length of the dark
matter at z~4 predicted from an analytic model by Peacock & Dodds but about
twice smaller than that of bright galaxies predicted by a semi-analytic model
of Baugh et al. We find an excess of omega(theta) on small scales (theta < 5'')
departing from the power law fit over 3 sigma significance levels. Interpreting
this as due to galaxy mergers, we estimate the fraction of galaxies undergoing
mergers in our LBG sample to be 3.0 +/- 0.9%, which is significantly smaller
than those of galaxies at intermediate redshifts.
