The present invention provides a simple aneuploid production process, applicable to all species, without producing unexpected damage to chromosomes other than a chromosome which is to be disappeared. A vector comprising two site-specific recognition sequences oriented in the opposite direction, or one site-specific recombinase recognition sequence comprising a point-symmetric nucleotide sequence, and a recombinase gene is introduced into a plant cells or a vector comprising two site-specific recognition sequences oriented in the opposite directions or one site-specific recombinase recognition sequence comprising a point-symmetric nucleotide sequence is introduced into a plant cell; a recombinase is allowed to act transiently in the cell during at least growth of the cell; and the cell is cultured and grown; and a cell in which a predetermined chromosome is disappeared is selected.