PURPOSE: To provide a method suitable for packing a heavy object such as distribution panel which is arranged following the predetermined procedures and packing spacers suitable for this packing method.

CONSTITUTION: In a method of packing a corrugated cardboard case 50 having an opening/closing upper surface with a heavy product 10 such as distribution panel, the heavy product 10 is taken apart into a main body 11, a bottom cover 13 and a top cover 12, corrugated cardboard-made spacers 20, 30 and 40 with U-shaped cross section are provided in the corrugated cardboard case 50 to support the main body 11 so as to form gaps between the main body 11 and each of the bottom surface of the corrugated cardboard case 50 and the top surface thereof, the top cover 12 is received in the gap between the main body 11 and the bottom surface of the corrugated cardboard case 50 and the bottom cover 13 is received in the gap between the main body 11 and the top surface thereof.