Apparatus and microchip for sorting micro particles

A micro-particle sorting apparatus comprising:

• a microchip in which a flow path through which liquid containing a micro particle flows and an orifice through which the liquid flowing through the flow path is discharged into a space outside the microchip;
• an oscillating element configured to transform the liquid into a liquid drop and discharge the liquid drop at the orifice;
• a charge means for adding an electric charge to the discharged liquid drop;
• an optical detection means that detects an optical property of the micro particle flowing through the flow path, upstream of a liquid-delivering direction with respect to the orifice;
• paired electrodes provided so as to be opposed to each other while sandwiching the moving liquid drop therebetween along a movement direction of the liquid drop discharged into the space outside the microchip;
• and
• at least a container that collects the liquid drop passing between the paired electrodes,
• wherein a width of the flow path and a depth of the flow path within the microchip at a location of the orifice are set to be smaller than a width of the flow path and a depth of the flow path within the microchip at a location at which the optical property of the micro particle is detected by the optical detection means;
• and
• wherein the flow path is configured to gradually decrease within the microchip, from upstream of the orifice, in cross-section area perpendicular to the liquid-delivering direction between the location at which the optical property is detected and the location of the orifice.