A laser marking device includes a laser emission unit configured to emit a laser beam to a first surface of an object to be processed, and a pressing unit configured to press a second surface that is opposite to the first surface of the object to be processed to make the first surface of the object to be flat. The pressing unit includes a first pressing portion configured to press an edge area of the second surface in a contact manner, and at least one second pressing portion configured to press a middle area of the second surface in a non-contact manner to maintain a separation distance from the second surface within a certain distance.