In a multi-tenant information processing system, when initially constructing a tenant, design items depending on the tenant are specified for each device constituting the tenant, and design values of the design items are calculated without overlapping with those of other tenants. In a tenant design item management table, the design items set for the devices and information indicating whether the design items depend on the tenant, are stored for each device. In a design algorithm management table, calculation formulae for making the design values to be different for each tenant are stored corresponding to the design items. A tenant design unit refers to the tenant design item management table, specifies the design items depending on the tenant among those corresponding to the devices constituting the tenant, calculates the design values of the design items according to the calculation formula, when initially constructing the tenant.