PURPOSE: To provide a padlock which has high resistance and can be sealed by hinging a sealing lid covering the surface of a lock device except an operation hole on a main body, and fixing the lid on the main body only when a bail is pushed into the prescribed position of the main body for locking.

CONSTITUTION: A main body 1 is formed out of a bail 2 inserted with a short leg 3 and a long leg 4, and an outer cylinder 5 inserted with an inner cylinder 7 having a key hole 6, as a pin tumbler lock. Next when the bail 2 is brought down for locking, an unlock pin 17 is projected in a inclined groove 18 by receiving the pressure of a fixing pin 15, the pin 15 is brought down by the action of a small spring 16, and the extreme end part 15a is projected in a fixing projection receiving part 14 and stopped. Next when sealing paper is placed in a receiving part 1a and the receiving part la is closed with a sealing lid 8, the extreme end part 15a is pushed up by the umbrella shaped part 12 of the fixed projection 11 of the lid 8, and depressed in a contracted diameter part 13 so as to fix the lid 8 on the main body 1. Unless a key is inserted into the hole 6 through the sealing paper and operated, the unlocking is impossible.