A slave server with an optimal response time with respect to a program can be selected from slave servers located near a client. A virtual-machine dynamic allocation system according to the present invention in which a master server dynamically allocates a virtual machine that is to execute a requested program to any one of slave servers, includes: a response-measurement-time-information measuring unit configured to measure response-time information about a period between transmission of a request signal from each slave server to each of programs operating in the master server and reception of a response signal from each program in the master server; a response-time-information storage unit configured to store the measured response-time information of each program for each slave server; and a slave-server determining unit configured to refer to the response-time-information storage unit so as to determine a slave server that is to execute the requested program.