This is a woodlouse (Armadillidium vulgare), or pillbug. They roll up into a little pill-like ball when disturbed. I keep a few of them in my snail tank to help keep it clean of snail poop and uneaten bits of food.
Woodlice are the only crustaceans (related to crabs and lobsters) to live on dry land. They are not a true insect.
I once wrote a haiku about woodlice and their many common names:
pillbugs and sowbugs,
what is in a name?