It is called “Juzu”. 数珠 I use it in some ceremonies or funerals of buddist. In these ceremonies, I usually hold it a hand. When a priest recite a sutras or I pray, I join my hands hanging it on one of my hand.
I think so, because Japanese Buddhist is quite easy one. So you can buy cheap juzu at some souvenir shops in some temples. But actually, I found that your photo’s one might be bracelet. Usually, they have bushy tassel.
You can wear “juzu bracelet” every day. But if you wear real “juzu” every day, it seems strange. Only priest or serious buddies do that. You can get juzu bracelet at some accessory stores or stone shops.