Iphone 6 in Shinsaibashi

Can I buy unlocked Iphone 6 directly to the Apple Store? Or do I need to pre-order it?

You can normally, but since it just came out, they may or may not have stock of certain models/sizes/colors depending on which you want. I think you should call ahead of time (English is okay) and check if they have the one you want, or will get some in when you plan to buy. If they don't have it, they can probably take a reservation over the phone. If you're planning to buy in December or something though, they most likely will have everything by that point.

BTW, I'm planning on switching too. My local Softbank store has all the iPhone 6 Plus sizes and colors, and the iPhone 6 in 128 GB in stock (all colors), but not the iPhone 6 16 or 64 gig in any color, just to give an idea of what places might or might not have now. They said it will take about a week to get it in once I order it.