It is called garlic chipper or cutter machine (actually it can also cut other fruit or vegetable like potato, carrot, giggle, mushroom, kiwi,ginger pitaya etc.) So sometime can named vegetable or

Fruit slicing machine.

this garlic slicing machine can be adjustable and cut the garlic or other fruits/vegetable into the size you need. Made of food grade stainless steel for keep the health, the working efficiency

Is so high than it can be instead of the operation by hand.