Lishkas HaMetzora'im - Chamber of Metzorah's

A Metzorah is someone who suffers from Tzara'as (similar to the modern day leprosy) - an illness inflicted by G-d as a punishment for certain misdeeds.

After the Metzorah was cured, he was required to come to the Beis Hamikdosh and immerse himself in a ritual bath situated in this room. Afterwards he would bring sacrifices that would complete the purification process.