Abstract: A spatial design system includes an acquirer, a generator, and a design information outputter. The acquirer is configured to acquire layout information on a space in a facility, environment information on an environment to be controlled in the space, and a target value of an effect which a person in the space is to obtain from a space design for the space. The generator is configured to acquire, based on the layout information, the environment information, and the target values, planting design information on a design for a plant to be arranged in the space. The design information outputter is configured to output the planting design information.