Store in Tokyo for power plug adaptor?

I'll need to find power plug adaptor for CEE7/4 ( www.powercords.co.uk/images/cee74.jpg ) to Japan's one. Anyone knows where to go in Tokyo? thanks in advance.

Is this for a laptop? If so, and the transformer is a standard figure 8 connection like this:

http://www.powercords.co.uk/pc108.htm

Just buy a figure 8 cable in Japan. You can find them at any electrical or computer store. This works out a lot cheaper than buying adapters, although you can pick them up at the airport you are travelling from or at somewhere like Tokyu Hands department stores in Japan.

For anything electronic related, go to Akihabara (JR Akihabara, Yamanote line). I would start at Yodobashi (big, giant store, hard to miss). After that, there are tons of small stores all over the place there.