A plant cultivation method includes providing a growth period and a rest period alternately. In the rest period, a dark period and a bright period is alternately provided. In the dark period, an intensity of light applied to a cultivation target plant is lower than a light intensity at a light compensation point. In the bright period, blue light whose wavelength is 400 nm to 500 nm is applied at an intensity that is lower than the light intensity at the light compensation point. A one-cycle time T of repetition of the dark period and the bright period is 2 μs to 500 μs. A duty ratio Δ；T/T of a bright period time Δ；T to the one-cycle time T is 20% or smaller. The blue light has a photosynthetic photon flux density of 0.001 μmol·m−；2·s−；1 to 4.0 μmol·m−；2·s−；1.
