Patent ID: 7936939

Claim:
A microinjection apparatus that injects an object into a cell on a base surface with a needle, the microinjection apparatus comprising: an image acquiring unit that acquires a plurality of images of the cell at different focal positions; a state deciding unit that decides a state of the cell based on a difference image obtained from a first image and a second image included in the plurality of images; a first focal position detecting unit that detects a first focal position of the image acquiring unit at which a differential aggregate distribution according to focal positions of a first focal point interval assumes a maximum value as calculated based on difference images obtained from the first image and images of the cell acquired by the image acquiring unit at the focal positions of the first focal point interval, at an observation position on the base surface at which the state of the cell is measured by the state deciding unit; and a second focal position detecting unit that detects a second focal position of the image acquiring unit at which a differential aggregate distribution according to focal positions of a second focal point interval assumes a minimum value as calculated based on difference images obtained from the first image and images of the cell acquired by the image acquiring unit at the focal positions of the second focal point interval narrower than the first focal point interval, at the observation position, each of the focal positions of the second focal point interval being within a predetermined range from the first focal position detected by the first focal position detecting unit.