The invention relates to an adjusting device for installing gaps of corn machine header working components. The adjusting device comprises an adjusting rod, first adjusting parts, a second adjusting part, branched adjusting rods and two third adjusting parts. The first adjusting parts are perpendicularly arranged at the two ends of the adjusting rod, and the width of the first adjusting parts is equal to the standard value of the gap between the ear picking plates. The second adjusting part is perpendicularly arranged between the two ends of the adjusting rod and is perpendicular to the first adjusting parts, and the thickness of the second adjusting part is equal to the standard value of the gap between the stem pulling rolls. The branched adjusting rods extend to the two sides from the middle of the adjusting rod, the two third adjusting parts are perpendicularly arranged at the two ends of the branched adjusting rods respectively, and the distance between the two third adjusting parts is equal to the standard value of the gap between the stopping chain plates. The adjusting device is simple in structure and convenient to operate, assembly work can be independently completed by one person, on the premise that product assembly quality is guaranteed, time and labor can be saved, and working efficiency is improved.