Evaluating the innate value of objects is critical for expressing adaptive behaviors. The value of odor objects, in particular, has salient hedonic aspects whose assessment switches the behavioral output between approach and avoidance. Although the amygdala and the lateral horn (LH) in mammalian and insect brains are implicated in driving innate olfactory behavior (Heimbeck et al., 2001; Root et al., 2014), whether and how these areas compute innate value of odors remain largely unknown, let alone the underlying circuit mechanism. Here we recorded the activity of virtually all the neurons in the Drosophila LH, and found that opposing odor values are represented by distinct neurons constituting differential circuit motifs. The decoding accuracy of odor value was higher in the LH than in the primary or the other second-order olfactory area, revealing the LH as a site of odor value computation. A connectome-based spiking network model recapitulating the activity of LH indicated that representations of aversive o