PURPOSE: To provide a method for detecting the presence or absence of liquid leakage constantly on dispensing and its dispensing device.

CONSTITUTION: The dispensing device forms light beams 20 by a near infrared light-emitting diode 14, a lens 16 for converting injected near infrared rays to parallel light beams, and a cylindrical lens 18 for constricting the parallel light beams to a size in the axial direction of a chip 36, and the light beams 20 has a beam width which is wider than the width of the axis of the chip 36. Therefore, when one part of a specimen 12 drops as a liquid ball from the tip of the chip 36, the liquid ball and the light beams 20 always cross each other. Then, a liquid leakage detection circuit 26 inputs the quantity of constant transmission light when the chip 36 moves via an optical filter 22 and a photo detector 24 at a light reception part and then outputs the signal of 'Liquid leakage occurrence' on a monitor 28 when it detects a rapid change in the level of quantity of transmission light and also displays a message indicating liquid leakage and gives a warning.