A management method for managing a plurality of virtual machines executing on an information processing apparatus (1A, 1B, 1C) which is connected to an allocation management apparatus and a load balancing apparatus, each one of the plurality of virtual machines executes at least one of a plurality of application programs that include a first application program whose performance is guaranteed not to drop and a second application program whose performance is not guaranteed, whereby the performance guarantee implies a priority of allocation of the virtual machines and is stored as contract data, the method comprising: detecting, by the allocation management apparatus, that a value related to a load of a first virtual machine that executes the first application program is equal to or greater than a first predetermined threshold; identifying (S15, S17), by the allocation management apparatus, a second virtual machine that executes the second application program by using a data storage unit that stores, in association with identification information of an application program, identification information of a virtual machine that executes the respective application program; requesting (S19, S21), by the allocation management apparatus, the information processing apparatus (1A, 1B, 1C) to stop the second virtual machine; requesting, by the information processing apparatus (1A, 1B, 1C), the load balancing apparatus to stop allocating processing to the second virtual machine, upon detecting that the management apparatus requested to stop the second virtual machine; stopping, by the load balancing apparatus, allocating processing to the second virtual machine when the load balancing apparatus receives the request from the information processing apparatus (1A, 1B, 1C) to stop allocating processing to the second virtual machine; determining (S27, S49), by the information processing apparatus (1A, 1B, 1C), whether a value related to a load of the second virtual machine is equal to or less than a second predetermined threshold; stopping (S29, S51), by the information processing apparatus (1A, 1B, 1C), the second virtual machine, upon determining that the value related to the load of the second virtual machine is equal to or less than the second predetermined threshold; and activating(S31, S51) by the information processing apparatus (1A, 1B, 1C), a third virtual machine included in the plurality of virtual machines to start processing (S33, S55) for the first application program; notifying (S35, S37, S57, S5, by the information processing apparatus (1A, 1B, 1C) about changes in the allocation of virtual machines to update (S38, S61) the stored contract data detecting, by the allocation management apparatus, that a value related to a load of a first virtual machine that executes the first application program is equal to or greater than a first predetermined threshold; identifying (S15, S17), by the allocation management apparatus, a second virtual machine that executes the second application program by using a data storage unit that stores, in association with identification information of an application program, identification information of a virtual machine that executes the respective application program; requesting (S19, S21), by the allocation management apparatus, the information processing apparatus (1A, 1B, 1C) to stop the second virtual machine; requesting, by the information processing apparatus (1A, 1B, 1C), the load balancing apparatus to stop allocating processing to the second virtual machine, upon detecting that the management apparatus requested to stop the second virtual machine; stopping, by the load balancing apparatus, allocating processing to the second virtual machine when the load balancing apparatus receives the request from the information processing apparatus (1A, 1B, 1C) to stop allocating processing to the second virtual machine; determining (S27, S49), by the information processing apparatus (1A, 1B, 1C), whether a value related to a load of the second virtual machine is equal to or less than a second predetermined threshold; stopping (S29, S51), by the information processing apparatus (1A, 1B, 1C), the second virtual machine, upon determining that the value related to the load of the second virtual machine is equal to or less than the second predetermined threshold; and activating(S31, S51) by the information processing apparatus (1A, 1B, 1C), a third virtual machine included in the plurality of virtual machines to start processing (S33, S55) for the first application program; notifying (S35, S37, S57, S5, by the information processing apparatus (1A, 1B, 1C) about changes in the allocation of virtual machines to update (S38, S61) the stored contract data