  We study the multiloop amplitudes of the light-cone gauge closed bosonic
string field theory for $d \neq 26$. We show that the amplitudes can be recast
into a BRST invariant form by adding a nonstandard worldsheet theory for the
longitudinal variables $X^{\pm}$ and the reparametrization ghost system. The
results obtained in this paper for bosonic strings provide a first step towards
the examination whether the dimensional regularization works for the multiloop
amplitudes of the light-cone gauge superstring field theory.
