A method for selecting a silicon single crystal substrate for controlling carrier recombination lifetime, comprising: a preparation step (S11) of preparing a silicon single crystal substrate as a candidate for the silicon single crystal substrate by fabrication from a silicon single crystal ingot grown by a floating zone melting method, FZ method; a particle beam irradiation step (S12) of irradiating the prepared silicon single crystal substrate with a particle beam; a measurement step (S13) of injecting excess carriers into the silicon single crystal substrate after the particle beam irradiation step (S12) and measuring a decay curve of an excess carrier concentration, excess carrier decay curve, in relation to time elapsed after injecting the excess carriers, wherein a microwave photoconductive decay method is used as a method for measuring the decay curve; a judgement step (S14) of obtaining, in the measured excess carrier decay curve, a decay time after which a remaining excess carrier concentration reaches a tail portion of the decay curve, wherein the tail portion is defined as the region in which the remaining excess carrier concentration is 10% or less of the excess carrier concentration at the time of injection and judging the silicon single crystal substrate as acceptable when a value of the decay time is a predetermined judgement value or less; and a selection step (S15) of selecting a silicon single crystal substrate fabricated from the same silicon single crystal ingot as the silicon single crystal ingot from which the silicon single crystal substrate judged as acceptable in the judgement was fabricated as the silicon single crystal substrate for controlling carrier recombination lifetime. a preparation step (S11) of preparing a silicon single crystal substrate as a candidate for the silicon single crystal substrate by fabrication from a silicon single crystal ingot grown by a floating zone melting method, FZ method; a particle beam irradiation step (S12) of irradiating the prepared silicon single crystal substrate with a particle beam; a measurement step (S13) of injecting excess carriers into the silicon single crystal substrate after the particle beam irradiation step (S12) and measuring a decay curve of an excess carrier concentration, excess carrier decay curve, in relation to time elapsed after injecting the excess carriers, wherein a microwave photoconductive decay method is used as a method for measuring the decay curve; a judgement step (S14) of obtaining, in the measured excess carrier decay curve, a decay time after which a remaining excess carrier concentration reaches a tail portion of the decay curve, wherein the tail portion is defined as the region in which the remaining excess carrier concentration is 10% or less of the excess carrier concentration at the time of injection and judging the silicon single crystal substrate as acceptable when a value of the decay time is a predetermined judgement value or less; and a selection step (S15) of selecting a silicon single crystal substrate fabricated from the same silicon single crystal ingot as the silicon single crystal ingot from which the silicon single crystal substrate judged as acceptable in the judgement was fabricated as the silicon single crystal substrate for controlling carrier recombination lifetime. <EOS>