The present invention provides a waterproof structure for a conductive path which waterproofs a conductive path without imposing an unnecessary load on a conductor, and can sufficiently obtain a creepage distance.A plurality of grooves 9 is formed on the outer circumferential surface 8 of an insulator 7. The grooves 9 are formed to be hollow by heat or cutting. The grooves 9 are formed within a predetermined range L on the outer circumferential surface 8 of the insulator 7. This predetermined range L is set as a range in which an overmold part 5 is provided. The overmold part 5 is a seal member made of an elastomer, and is disposed and formed within the predetermined range L of an electric wire 2. Also, the overmold part 5 is formed to fill all of the three grooves 9.