Search "ginza lingerie" in Google Maps. Ginza has most of the lingerie market covered.
B2F of the NishiGinza "mall" is basically dedicated to lingerie. It is like Victoria Sports - but for lingerie.
In addition to La Perla, Wacoal has an upmarket brand "Wacoal Dia". They have a nice boutique in the expensive lanes of Ginza. Search for Wacoal Dia on google maps.