Laser processing apparatus

A laser processing apparatus comprising:

• a holding unit including a holding table adapted to hold a plate-shaped workpiece;
• a laser beam applying unit adapted to apply a laser beam to the workpiece held by the holding table to process the workpiece;
• and
• a liquid supply mechanism disposed on the holding unit,
• wherein the liquid supply mechanism includes:
• a pool adapted to form a layer of a liquid on an upper surface of the workpiece held by the holding table;
• a transparent plate disposed such as to make contact with the layer of the liquid;
• a jet nozzle adapted to jet the liquid toward an application position of the laser beam applied to the workpiece through the transparent plate;
• a liquid supply nozzle adapted to supply the liquid from one side of the pool;
• and
• a liquid discharge nozzle adapted to discharge the liquid from other side of the pool.