To provide a wire clamping device in a transfer vehicle which can manufacture a workpiece at a low cost by a simple constitution while attaining improvement of reliability in conveying of the workpiece and production efficiency.

A first clamp part 352, by eccentrically placing a wire clamping surface 398 of a cam 360 relating to a rotary shaft 370 and eccentrically placing a wire clamping surface 399 of a cam 362 relating to a rotary shaft 372, clamps a wire 20 when it is rotated in a forward direction (direction of arrow mark X1) and does not clamp the wire 20 when it is rotated in a reverse direction (direction of arrow mark X2). For making the wire 20 and the cams 360, 362 come into always contact, a spring 382 energizes the cam 360 and 362 in a direction of arrow mark X3 by its elastic force. Accordingly, the first clamp part 352 is self locked when the wire 20 is rotated in the forward direction (direction of arrow mark X1).