Washing agent pump and laundry treating apparatus having the same

A laundry treating apparatus, comprising:

• a cabinet;
• a tub provided within the cabinet;
• a rotary tub provided within the tub in a rotatable manner;
• and
• a washing agent supply unit that includes
• a storage container to store a liquid washing agent including a liquid detergent or a liquid softener, the storage container being slidably provided in the cabinet,
• a washing agent supply passage having one side connected to the storage container and another side connected to the tub, and
• a washing agent delivery device provided in the washing agent supply passage to deliver the liquid washing agent to the tub,
• wherein the washing, agent delivery device is a washing agent pump, and
• wherein the washing agent pump includes:
• a passage body having a passage for the liquid washing agent and a pressurized space, and provided with an intake valve that, opens and closes an inlet port of the pressurized space and a discharge valve that opens and closes an outlet port of the pressurized space;
• a cylinder provided at one side of the passage body and in communication with the pressurized space;
• a piston provided within the cylinder in a reciprocating manner;
• and
• a residual quantity detecting unit including an air pocket cavity in communication with the passage formed in the passage body, the air pocket cavity configured to temporarily store therein air and the liquid washing agent, and electrodes provided within the air pocket cavity and configured to come into contact with the liquid washing agent, wherein the residual quantity detecting unit detects a low level of the liquid washing agent in the washing agent supply unit.