Taiyaki Wakaba is a very famous taiyaki shop near Yotsuya station. They are around since 1895, so if you're looking for a classic taiyaki, this is the plance! You can have it to go, or you can sit inside to enjoy the taiyaki. You can have it with a cup of (free) green tea, which really balances out the sweetness of the read bean paste. Also, their dough is a bit saltier than the other shops, this really complements the red bean taste.
1 piece is ¥150, you can also buy red bean paste and shaved ice (perfect for the summer!)
Naniwaya, in Azabajuban right next to the station, was founded in 1909 and is around ever since. Their dough is thinner than other shops, so they are really about the red bean paste! Their taiyaki are ¥150 each, and you can have them to go or in the cafe. They also have other sweets to try, such as shaved ice and cake.
Taiyaki Hiiragi is in Ebisu, a few minutes from the station. They only have a bench in front of the store, or you can take it to go This place is very popular and has great taiyaki as well. Their taiyaki goes perfectly with green tea, but there also many delicious coffee shops in Ebisu (Saruhatiko). The taiyaki is ¥150 each. Would you like to try it with ice cream? Yum!
Ajisaki is located in Minamiikeburo in Seibu Ikebukuro. This shop has many creative flavours if you want a twist on the classic. How about curry flavour or apple pie? Yum! Why not give it a shot! You definitely need to try the matcha taiyaki, it even has mochi inside! Nom nom nom!
They also have soft-serve ice cream amongst other things if you want something to go with your taiyaki. They're about ¥180 each.
Gindaco is a chain and has over 20 branches all over Tokyo, such as Harajuku, Ebisu, Ueno, etc. They specialise in takoyaki (an Osaka specialty), but they have sweets too! For a twist on the original taiyaki, you can also try the "croissant taiyaki" its a taiyaki with a flakey, buttery crust. It's definitely a must-try. Walking by this shop, is such a pleasure with the sweet caramel smell lingering in the air, can you fight temptation? They are about ¥280.