PURPOSE: To improve production efficiency by coping with the shape change of a substrate only by progressing the cutoff of a unit substrate with tracing a cut line and changing the moving program of X - Y table, in a dividing device of an electronic circuit board.

CONSTITUTION: When a multi-chamfer board 2 fitted with electronic parts is placed on support members 8, 9 with its being transferred, cutting edges 20, 40 coincide with a specific cutting line. X - Y table 14 is then moved so that the cutting edges 20, 40 coincide with a cutting line 4, the cutting edges 20, 40 are approached and a link part 6 is ruptured. Then, spline shafts 30, 50 are rotated so that the sub-direction of the cutting edges 20, 40 coincide with the line 4. Once again, the cutting edges 20, 40 are located by the table 14 so as to coincide with the line 4 and the same operation is repeated. The link part 6 is ruptured in order along the outer periphery of the unit board 3 and the board 3 having completed rupture is stored in a receiving box 18 by being slipped down on a chute 16. After completion of the rupture of the link part 6 a scrap 7 is taken out.