An apparatus comprising: a sprayer for inoculating a microbe on a first division divided from at least one sample of a plant to be examined; sample leaving device for leaving a second division divided from the sample not inoculated with the microbe and the first division inoculated with the microbe, for a predetermined period of time under a predetermined condition; first and second photodetector for respectively measuring the quantities of luminescence emitted from the first and second divisions which have been left standing by the sample leaving device; and a computer for comparing the quantities of the luminescence measured by the first and second photodetector, thereby to examine the resistance or sensitivity of the plant to the microbe.
