In a cutting machine for cutting down venetian blinds a headrail cutter and a bottom rail cutter are provided which move along a horizontal axis. After the headrail and bottom rail are trimmed a slat cutter moves in a vertical axis, up or down to cut the slats. The cutting machine enables one to cut down a venetian blind while the opposite end of the blind remains in the packing box. Preferably, a spacer or collar is provided on the blind prior to packaging so that the headrail, window covering material and bottom rail will be spaced apart from one another a desired amount. That spacing should be the same spacing as the openings in the cutting machine so that when one end of the blind is removed from the package that end of the blind can be readily inserted into the cutting mechanism.