Buying electricity adaptor in Tokyo

I am travelling to Japan for the first time in October. As I find it very important, can I please get an answer where is it most convenient to buy an electricity adaptor in Tokyio or Narita airport? Thank you!

Any good electronics store in the city or airport will carry them, however it may be easier to purchase one in your home country before you travel.

Depending on what country you're coming from, your electronics might work without one.

Unfortunately, plugs and sockets are entirely different in my country and electricity is 220V.

In that case you may need more than an adapter. Check you devices for their input voltage. If they say 100-240v or something like that then you'll just need a plug adapter. Otherwise you may need a step up transformer too which tend to be big, heavy and expensive.

Are you talking about plug adaptor?

What electrical appliances are you bringing/trying to use in Japan.
Know that most ELECTRONIC devices have universal converter 100V~240V 50/60hz.
So check properly,as mention by yllwsmrf. No point bringing 220V appliances to Japan and buying a step-down transformer.

I am bringing only 3, but most important, a camera, a smart phone and a regular mobile phone. Although a Canon, the camera's charger is 220 - 240V.I think I will need a power adaptor as well as the socket.
Thanks for all suggestions.

Get one before you come.
It may seem hard to find a Japanese adapter but american ones are pretty much the same.

The voltage thing generally isn't an issue either when you go to Japan- Japan has the weaker electrics so a old European device simply wouldn't work or would work slowly/weaker than normal.
Its going the other way with Japanese devices in Europe where things can get dangerous.
Though these days most modern electricals work with a large range of voltages. Its only really with very old things and stuff like hair driers that they don't.

For the Canon, I would go buy a Japanese battery charger instead of a step up transformer.

Thanks for the latest replies!