Where is the Hgh end Shop in TOKYO ?

Dunno if it's a must-see, but check out Yodobashi Camera. There's an outlet in Akihabara (locals call it "Akiba").

 

Currawong made a thread about it here:

http://www.head-fi.org/forum/thread/515718/blog-a-trip-to-yodobashi-camera-and-the-shure-sh-440-and-sh-840

I'd say Akihabara is a 'must see' area. 

This should give you an idea.

http://www.tnt-audio.com/tours/akihabara_e.html

 

However, there are bunch of other areas that you might enjoy. Shinjuku where Yodobashi started is one of the most crowded area even in Tokyo. And folks working at the Apple Store in Shibuya were not chatting with each others like the one here in Glendale, CA. You can actually get their attention by just walking in :P

Yodobashi is definitely a must.  That place is so huge- it's a good thing they have a nice set of eateries on the top floor or I would've starved to death after looking at all of their stuff!  The cool thing about a lot of stores in Japan is they often have most of their IEMs (except for their most esoteric ones) on display so you can listen to them.  And the displays also have alcohol wipes so you can clean the tips before you stick them in your ears.  Although you're kinda not supposed to take pictures inside the stores, I couldn't resist and sneaked a few:

 

This is a set of booths (on the left) where you can demo some of their better headphones.

 

Not for headphones, but just to show you the kind of place this is- that's part of their selection of tubes.

 

Akihabara is great but lately it is more geared towards 'otaku' culture- comics, idols, maid cafes, etc.  If by chance you will also be in Osaka, there is a place there called Den-Den town that reminds me of the 'old' Akihabara.  There are at least a couple of stores there with nothing but high-end audio gear and huge IEM displays.

I've been to akihabara twice in the three years i've lived in Japan... be warned you really have to hunt for anything useful there.  I was expecting it to be an amazing electronics experiance and I was quite disappointed. 

 It really has changed, especially since the 80s. Back then there were things you could only get there and they were cheaper than buying in the US. But then again the exchange rate was ¥230 compared to the ¥80ish we see today. My guess is the same thing happened over there as here- big box stores like BIC, Joshin, and Yodobashi took over just like Circuit City, The Goodguys, and Best Buy did here. That said, I'll take Yodobashi over Best Buy ANY day of the week. That's why I was fairly pleased to see a few nice stereo shops left in Osaka when I went there last year. I hope to make it over there this year!

All the small, interesting computer stores were killed off by the rise of cheap components from China, homogination of technology and can only profit on selling laptops now. However, note that when you're in Japan, second-hand stores don't just have a spread-out ground-floor location, they are often in tiny buildings with multiple floors.  There may still be a couple of second-hand audio stores that have speakers on the ground floor, cables on 2, high-end on 3 etc.  You'll have to really hunt to find them though.

 

One of the multi-location hi-fi stores used to have a dedicated headphone store where you could try all the TOTL headphones with basically decent gear, but it is no longer a headphone store from what I gather.  Yodobashi is amazing, but it's very noisy.  If you're getting a rail pass (a must for saving on travel) you're welcome to come by Fukuoka (Hakata station, currently the end of the line until later this year) and meet up with Lobstersan and I. We might be able to set up a bit of a listening session too, though we've cut down a lot on the amount of gear we own.  There is a Best Denki here with a high-end headphone table in a not-too-noisy area we can visit too. It is loaded with Denon, Sony and AT at the moment.