A growth state measuring device for a
crop in cultivation is provided, which can continuously measuring the nutritional state of the
plant in a non-contact, non-destructive manner at a cultivation site such as
open air or indoors with respect to the cultivated
crop at the growth stage before harvesting. The growth state measuring device for the
crop in the cultivation according to the present invention includes a
light source (11), a light projection
control unit (12), a light receiving unit (13), a light receiving
control unit (14), and a calculation unit (15). The
plant (1) is a crop in thecultivation stage before the harvesting. Measurement sites (1a), (1b), (1c) are any one of a stem, a fruit
handle, and a petiole, and the
living body holding structure is attached to a stem, a fruit
handle or a petiole. In the calculation unit (15), the arithmetic
processing is performed using the difference between a light-receiving
signal, at the time of light projection, obtained by the detection light at the time of
irradiation by the
light source (11) and a light-receiving
signal, while the light projection is not performed, obtained by the detection light before or after
irradiation timing.