A plastic film cutting device includes: a casing adapted to receive a roll of a plastic film therein and having an open end that defines an access opening for access into the casing, and a lid connected to the open end for covering and uncovering the access opening, the lid having first and second ends opposite to each other in a lengthwise direction; and a cutting unit including a first cutting member disposed in the casing, movable between the first and second ends of the lid in the lengthwise direction, and abutting resiliently against the lid for cutting the plastic film therebetween.