PURPOSE: To easily evade a trouble and to perform the treatment for a claim because a forgery and an alteration can be prevented by preliminarily printing the pattern by oblique lines in a lot drawing number part with stealth ink in a betting ticket and checking the continuity of the oblique line.

CONSTITUTION: When a betting ticket is printed, a lot drawing number is preliminarily printed by a normal visible printing and the pattern of oblique lines is printed on the whole clear zone of the lot drawing number part for every betting ticket at random with stealth ink. When the betting ticket is collated, the visible lot drawing number is read by a normal printing reading part 3, the number is collated with a storage part 11 storing winning numbers, the discrimination of a success or defeat is performed, and at the same time, the continuity of each pattern read by a stealth printing reading part 4 is checked and whether a forgery or an alternation such as an unfair sticking, etc., exists in the lot drawing number part or not can be checked by checking whether all the patterns become straight lines or not.