Abstract: The present invention relates to a shield mounting device for a helmet shield in which a helmet shield can be easily assembled and disassembled to/from a helmet body. The shield mounting device for a helmet comprises a mounting protrusion having a flange at an edge thereof; a mounting plate having an arc shaped groove capable of guiding an operation that the flange is inserted and rotated; a base plate having an elastic piece elastically moving in a direction that an external force is applied when the external force is applied to the mounting protrusion; and a locker having an escape prevention for preventing an escape of the mounting protrusion.