There is provided a helmet including a shield having inner coupling holes at both ends thereof and fitted and coupled to an assembly coupling hole of a shield coupling assembly provided at a helmet main body and a front opening configured to be opened and closed by the shield. The helmet includes: a lock supporting member fixed to the helmet main body; and a locker including a shield mounting portion fixed to the shield, a coupling shaft coupled to be rotated with the shield mounting portion at an end of the locker, and a locker hooking part coupled to or decoupled from the lock supporting member at the other end of the locker.