  We have carried out a brown dwarf search over an area of 14' x 23' near the
central portion of the Pleiades open cluster in five optical and near infrared
bands (i', Z, J, H, Ks) with 10 sigma detection limits of i' = 22.0, J = 20.0
and Ks = 18.5 mag. The surveyed area has large extinction in excess of Av = 3
in the Pleiades region. We detected four new brown dwarf candidates from the
colour-colour (J-K, i'-J) and the colour-magnitude (J, i'-K) diagrams. We
estimated their masses as 0.046 Msun down to 0.028 Msun. The least massive one
is estimated to have a mass smaller than Roque 25 or int-pl-IZ-69, and maybe
the lowest mass object found so far in the Pleiades cluster.
