To eliminate the need of a linear movement guide member by improving a linear movement/rotating movement converting and transmitting mechanism.

This barrier 50 comprises a lever holding mechanism 31 capable of holding a barrier lever 10, a spindle 32 positioned horizontally and rigidly connected to the lever holding mechanism 31, a drive part 40 having a ball screw mechanism 43 and 44, and a transmission mechanism converting the linear motion of a nut part 44 to the rotating motion of the spindle 32. An auxiliary shaft 51 is installed horizontally, a ball screw shaft 43 is rotatably supported on the auxiliary shaft 51, and a driven member 33 rigidly connected to the spindle 32 and a connection member 52 and 53 engaged with the nut part 44 in a hinged state are installed in the transmission mechanism. Since the linear motion of the nut 44 is converted into the rotating motion of the spindle 32 without applying a bending force to the ball screw mechanism, the linear movement guide member which was required before can be eliminated.