PURPOSE: To prepare various courses with stable quality and to form the course, which can be known for the first time when self-traveling is executed, by printing ink to include metal powder, whose diamagnetic constant is ≥ a specified value, on a sheet to be composed of paper or plastic.

CONSTITUTION: A self-traveling toy vehicle 3 with magnet is magnetically guided and traveled on a base material 1, to which a traveling course 2 is printed. It is optimum on handling for the traveling course 2 to be printed on the flexible base material 1 such as the paper, plastic sheet or a plastic film, etc. In the metal powder ink to be used for the printing, for the metal powder, metal, whose diamagnetic constant is 500, is powdered. As the printing method of the traveling course, photogravure printing or silk screen printing is suitable. When the thickness of coating is increased, the silk screen printing method is optimum. Since the traveling course 2 is prepared so as not be known at a glance, the printing of the metal powder is executed to the rear of the traveling sheet. When the metal powder is printed on the front surface of the sheet, the other printing ink is overlapped and printed and the traveling course is covered with the ink.