To provide a work piece conveying apparatus and machining system installable without any increase in area and height for installation, and considering the safety of a worker.

This work piece conveying apparatus for conveying work pieces to spindle moving type vertical machine tools 1a, 1b, includes a guide member 71 extended parallel to a second direction in a position on the opposite side of a work area of the worker to the bases 2a, 2b of the spindle moving type vertical machine tools, a traveling body 72 provided on the guide member movably in the second direction, work piece holding members 721, 722 provided on the traveling body to be moved up and down and capable of holding the work piece, and work piece moving pats 3a, 3b capable of transferring the work piece to and from a chuck in a first transfer position A on a moving locus in the second direction of a spindle, transferring the work piece to and from the work piece holding members in a second transfer position B on the moving locus of the work piece holding member and moving the work piece between the first transfer position and the second transfer position.