alps makes this type of encoders
Yes, thank you! the seems to be the right place! Now I've to find a dealer.
Silly as it may seem, another mouse?
Thank you too! It's not silly, for the click button, in example, I've used another mouse couse most of good mice use an Omron micro switch.
But rotary encoder may be very different from one to another, at least in dimensions and pin configuration. I'll try to look for in every mouse I open.
You could also try removing it and cleaning the contacts.
I'll do it of course, but first I need a replacement, couse it's so small and something can always go wrong.
Thank you all for answers!