A device for detecting ovulation using saliva according to the present invention comprises: a device body having a lens disposed in the inner space thereof and a pinhole formed through a side opposite to the lens a scattering unit coupled to one side of the device body, which has the pinhole formed therein, and configured to scatter light to be supplied to the pinhole and a sample plate which is separably mounted in the device body so as to be located between the lens and the pinhole and on which saliva is placed, wherein the pinhole is configured to convert light, which passed through the scattering unit, into point light so as to uniformly supply the light to the sample plate, so that saliva crystals formed by drying of the saliva will form a striking contrast with the surrounding portions when the light is scattered by the saliva crystals.
