No, its in sid/non-free.
So please ensure that you have added non-free really to your /etc/apt/sources.list.d/debian.list, run 'apt-get update' and 'apt-get install unrar rar-' should work fine.
(I have added 'rar-' to ensure that you don't have rar installed (by requesting its removal with the dash) which is also packaged and should have similar functionality but conflicts with unrar & is shareware…)
Thanks, Donkult.It works now. I have forgotten to add to the following non-free repositories:
"deb http://ftp.br.debian.org/debian unstable main contrib non-free
deb-src http://ftp.br.debian.org/debian unstable main contrib non-free".