PURPOSE: To make changing operations easier by a method in which the most backhanded dial of rotary dials in a dial-combination lock having a body and an insert to be fit into the groove of a shaft column projected from the body is moved to alter the combinations of the rotary dials.

CONSTITUTION: A shaft column 7 with a groove 6 is erectly provided on the center of a body 1, and an inlet 6a for a rod 10 projected from an insert 2 is formed. Mark numerals are carved in the peripheral sides of rotary dials 11, 21, and 22, an inner gear 12 is formed on the bottom of the inner surface 13, and an annular spring 14 is housed. A gear 16 integrated with an inner ring 15 is engaged with the inner gear 12. Under a condition that the rod 10 does not come in, the dial 11 is slid to the direction of the insert inlet 6a against the spring 14 to remove the gear 16 from the gear 12, and the dials 11, 21, and 22 are turned to set a desired conbination. The dial 11 is then returned to its original position. The changing operations can thus be easily made.