Hey Vishal

There are 2 IITs which offer B.Arch course:

1. IIT Roorkee , Uttarakhand

2. IIT Kharagpur , West Bengal

For admission to undergraduate architectural courses you must clear an entrance. 

1.If you clear JEE Mains paper 2 for B.Arch only you are eligible to get admission to NIT  for 5 yrs of degree

2. If you clear JEE Mains paper 1 for B.Tech then only you can appear for JEE Advanced and have to score there too. If you score an AIR in this exam then you'll be eligible for AAT i.e. Architecture Aptitude Test for IITs

So in all you have to go through JEE Mains , JEE Advance and AAT to get IIT for B.Arch

Hope this is helpful for you.

Hello Aspirant,
If you are desirous of pursuing B. Arch. in IIT Kharagpur or IIT Roorkee, you must clear the Architecture Aptitude Test (AAT).The contenders who have secured a rank in JEE Advanced are eligible to sit for AAT.The test will be be held only at the seven zonal IITs. This means, in order to get a B. Arch course in these two institutions, one has to clear Paper 2(B. Arch. / B. Planning.) of JEE Main, JEE Advanced and AAT.