Provided are an excreta detection device that is for a diaper and capable of detecting excreta present in the diaper, and an excreta detection reader for transmitting and receiving signals to and from the excreta detection device for the diaper and notifying a user about whether excreta is present. Since the large scale of a resonant frequency is determined on the basis of a capacitor which is isolated from the excreta and not affected by the excreta and the small scale of the resonant frequency that changes due to the excreta may be determined on the basis of a capacitor having a permittivity that changes due to the excreta, the excreta may be detected even when a relatively narrow frequency band is swept. In addition, since excreta sensing is not performed at only a specific resonant frequency but is also performed by comparing resonant frequencies before and after discharge of excreta, the excreta sensing can be performed regardless of the state of the excreta.
