An amplifier selection device includes: a storage means for storing a database containing information pertaining to motor models, amplifier capacities and feature amounts; a means that obtain information of motor models necessary to configure a desired system; a means that calculate a number of necessary amplifiers; a means that select spindle amplifiers; a means that create a combination of servo amplifiers for each spindle amplifier; a means that extract information pertaining to the feature amounts by referring to the database; a means that determine a combination on a basis of the information pertaining to the feature amounts; a power source capacity calculation means that calculate capacities of a main power source and a control power source by referring to the database; and a display control means that display the combination of amplifiers along with the main power source and control power source capacities.