LASER APPARATUS FOR FORMING PATTERN ON INSIDE OF WORKPIECE

A laser machining apparatus is provided to make it possible to form predetermined high quality patterns on the inside of a workpiece using a laser beam, and a double laser machining apparatus is provided to reduce production cost and make it possible to reduce a pattern-forming time. A double laser apparatus(200) is characterized in that: the apparatus comprises a laser light source part(210), a beam splitter(240), a first reflection mirror(260), a first lens(250), and a second lens(270); the laser light source part generates a laser beam; the beam splitter divides the generated laser beam into a first laser beam(LS1) and a second laser beam(LS2) to proceed the first laser beam to the first lens and proceed the second laser beam to the reflection mirror; the first reflection mirror reflects the second laser beam to the second lens; and the first and second lenses positioned in one of workpieces(12) to form patterns on the inner surface of the workpiece by projecting the first and second laser beams onto an inner surface of the workpiece.