  We discuss the role of deformation of the target nucleus in the fusion
reaction of the $^{15}$C + $^{232}$Th system at energies around the Coulomb
barrier, for which $^{15}$C is a well-known one-neutron halo nucleus. To this
end, we construct the potential between $^{15}$C and $^{232}$Th with the double
folding procedure, assuming that the projectile nucleus is composed of the core
nucleus, $^{14}$C, and a valance neutron. By taking into account the halo
nature of the projectile nucleus as well as the deformation of the target
nucleus, we simultaneously reproduce the fusion cross sections for the $^{14}$C
+ $^{232}$Th and the $^{15}$C + $^{232}$Th systems. Our calculation indicates
that the net effect of the breakup and the transfer channels is small for this
system.
