To provide an apparatus for spinning equipped with a device for evaluation capable of detecting a weak yarn with a high accuracy in good timing.

This apparatus for spinning is equipped with a device 51 for evaluation having a first means 53 for carrying out an averaging treatment of a waveform output, comparing the output waveform before the averaging treatment with the waveform output after the averaging treatment and detecting the reference point of time and a second means 52 for setting the reference value based on the waveform output before the averaging treatment at the reference point of time, comparing the waveform output before the averaging treatment with the reference value and detecting a weak yarn.