A tension device comprising: a feeding pulley configured to wind around it a wire rod fed from a wire rod supply source; feeding speed controlling means for controlling rotation of the feeding pulley and controlling speed of the wire rod pulled out from the wire rod supply source to move toward a winding machine; a movable first tension pulley configured to turn the wire rod fed from the feeding pulley; a movable second tension pulley configured to further turn the wire rod turned by the first tension pulley and direct the wire rod to the winding machine; and urging means (33, 34) for urging the first tension pulley and the second tension pulley to expand a space between these tension pulleys, characterized in that a pair of tension arms (31, 32) which are line-symmetrically formed are provided rotatably about proximal ends thereof, the first tension pulley is pivotally supported at a distal end of one of the tension arms and the second tension pulley is pivotally supported at a distal end of the other one of the tension arms, the urging means is formed of elastic members (33, 34) configured to apply, to the pair of tension arms (31, 32), elastic forces corresponding to pivoting angles of the pair of tension arms (31, 32), pivoting-angle detecting means for detecting the pivoting angle of one or both of the pair of tension arms (31, 32) is provided, and the feeding speed controlling means is controlled to control rotation of the feeding pulley to set the pivoting angle detected by the pivoting-angle detecting means to a predetermined angle, and disk gears (31b, 32b) that mesh with each other to set the pivoting angles of the pair of tension arms (31, 32) to a same angle are respectively attached to the proximal ends of the pair of tension arms (31, 32). a feeding pulley configured to wind around it a wire rod fed from a wire rod supply source; feeding speed controlling means for controlling rotation of the feeding pulley and controlling speed of the wire rod pulled out from the wire rod supply source to move toward a winding machine; a movable first tension pulley configured to turn the wire rod fed from the feeding pulley; a movable second tension pulley configured to further turn the wire rod turned by the first tension pulley and direct the wire rod to the winding machine; and urging means (33, 34) for urging the first tension pulley and the second tension pulley to expand a space between these tension pulleys, characterized in that a pair of tension arms (31, 32) which are line-symmetrically formed are provided rotatably about proximal ends thereof, the first tension pulley is pivotally supported at a distal end of one of the tension arms and the second tension pulley is pivotally supported at a distal end of the other one of the tension arms, the urging means is formed of elastic members (33, 34) configured to apply, to the pair of tension arms (31, 32), elastic forces corresponding to pivoting angles of the pair of tension arms (31, 32), pivoting-angle detecting means for detecting the pivoting angle of one or both of the pair of tension arms (31, 32) is provided, and the feeding speed controlling means is controlled to control rotation of the feeding pulley to set the pivoting angle detected by the pivoting-angle detecting means to a predetermined angle, and disk gears (31b, 32b) that mesh with each other to set the pivoting angles of the pair of tension arms (31, 32) to a same angle are respectively attached to the proximal ends of the pair of tension arms (31, 32).