A film cutter includes: a body unit having a gripping portion, a receiving portion, pivotal portion, a sliding portion, an access slit, and a film feeding opening; a movable knife having a pivotal connection portion pivotally disposed at the pivotal portion, and a cutting portion; an operating unit having a sliding portion disposed at the sliding portion of the body unit, an operating portion for driving the sliding portion, a knife controlling portion for actuating the movable knife to rotate about the pivotal portion and thus allow the cutting portion to be exposed from or to retract into the access slit; two blades disposed in the body unit and each having a sharp edge tilted at an angle relative to and corresponding in position to the film feeding opening; and a guide member mounted on the body unit and corresponding in position to the film feeding opening.