The invention discloses a roadblock device used for preventing converse running on a one-way lane. The device comprises a first-level wall body and a second-level wall body, a groove is formed betweenthe first-level wall body and the second-level wall body, and a cover plate is clamped with the first-level wall body and the second-level wall body; a through cavity is formed in the cover plate, aU-shaped pipe is embedded in the second-level wall body, pistons slidably and staggeredly sleeve the upper and lower ends of the U-shaped pipe internally and respectively, and steel wires are welded to the two pistons. The device has the advantages that a groove is formed in the surface of the one-way lane, a stressed baffle plate is utilized for driving a chain and a gear to rotate at a certain angle by taking a rotary shaft as a supporting point, so that the steel wire and the pistons are pulled, acting force of internal pressure intensity of the airtight U-shaped pipe on the pistons is utilized for flexibly supporting the steel wire and the chain under the joint effect of elastic force of a first-level spring, and therefore unidirectional rotation of the baffle plate is achieved, the certain buffering effect can be achieved under the reverse stress condition, the probability that the baffle plate is broken off is effectively reduced, and prolonging of the service life of the roadblock device is facilitated.