A liquid leakage detection system requiring no power supply from an outer source and configured to be relatively simple and moderate in price. A liquid leakage detection system (10) including an infusion tube (11), a syringe needle (12) coupled to the infusion tube (11), an absorbent element (16) adapted to be placed in the vicinity of a point (12a) of the syringe needle (12) to be pricked through a patient skin and a sensor unit (14) located on an upper side or within the absorbent element (16).