To control a bandwidth without the need for a large-capacity buffer. This invention provides a packet transfer apparatus connected to first device and second device, with a network therebetween, including: an input unit that receives a packet from the first device; a packet storage unit that stores the packet; a packet processing unit that stores the packet in the packet storage unit; a packet checking unit that checks whether the packet is related to data request; a packet analyzing unit that analyzes the amount of data requested by the data request; a transfer control unit that controls transfer of the packet on the basis of the analyzed amount of data; and an output unit that sends the received packet to the second device.