To provide an IC lead jointing method of a Hall IC to a terminal connection part 7 of a terminal in which caulking jointing can be carried out in a short time and inexpensively with a small space without requiring an expensive facility such as resistance welding and laser welding.

After inserting the lead connecting part 3 of each IC lead 2 of a Hall IC into a slit, two of a first and a second tooth portions 21, 22 are pressed from both sides in plate thickness direction of the two first and second tooth portions 21, 22 by four of a first to a fourth caulking pins 31-34 having respectively inclined faces 31a-34a and edge portions 31b-34b, and at least the slit wall face of the two first and second tooth portions 21, 22 is plastic deformed so that it may be convex in the narrowing direction of the slit width. Thereby, the lead connecting part 3 of each IC lead 2 of the Hall IC can be caulking jointed firmly to each terminal connecting part 7 of three terminals.