The present invention relates to a deployment guide mechanism for a roof airbag device that enhances assembly performance and productivity of the product by improving an assembly structure of a guide wire and a spring. The present invention discloses a deployment guide mechanism including a guide wire fixed to one side of a roof portion and provided in the lengthwise direction in which the roof airbag deploys, a guide housing fixed to the other side of the roof portion, a stopper supported in the guide housing and coupled to an end of the guide wire in a threaded coupling structure, and an elastic member providing an elastic restoring force to the stopper in the lengthwise direction of the guide wire toward the other side of the roof portion.