It depends on where you get it.
In most places, the LL.B. is an undergraduate degree similar to a Bachelor of Science (or Arts), but specific to the study of law.
Many law schools require applicants to already hold a Bachelor's degree (or at least have completed some ... usually two years ... of study at another college or university). However, this isn't universal, and the LL.B. is more properly regarded as a "first professional" degree than a "post-graduate" degree.
For that matter, despite having the word "Doctor" in the title, the J.D. isn't properly speaking a post-graduate degree either (many J.D. holders also hold Bachelor's degrees, but it's not strictly required).
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