Curtain cutting aid

A curtain cutting aid, comprising:

• a curtain holder comprising a first sidewall, a second sidewall opposite to the first sidewall, a top wall connected between said first sidewall and said second sidewall at a top side, a bottom wall connected between said first sidewall and said second sidewall at an opposing bottom side, an insertion space surrounded by said top wall, said bottom wall, said first sidewall and said second sidewall, an insertion slot transversely cut through said first sidewall in communication with said insertion space, a sliding slot disposed adjacent to said insertion slot, a cutting slot located in said top wall in vertical communication with said insertion space and a positioning portion located in said insertion slot;
• and
• a positioning unit comprising a movable bar, an operating knob and an elastic restoring member, said movable bar being movably inserted through said insertion slot in said first sidewall of said curtain holder into said insertion space, said movable bar comprising a plurality of positioning grooves arranged in parallel on a top wall thereof, said operating knob being mounted in said sliding slot of said curtain holder and movable between an initial position and a pressed position, said operating knob comprising an opening disposed in communication with said insertion slot and coupled to said movable bar in such a manner that when said operating knob is in said initial position, one said positioning groove of said movable bar is engaged in said positioning portion of said curtain holder;
• when said operating knob is in said pressed portion, each said positioning groove of said movable bar is disengaged from said positioning portion of said curtain holder, said elastic restoring member being mounted in said sliding slot in said first sidewall of said curtain holder and stopped against a bottom edge of said operating knob to support said operating knob in said initial position.