Proposed is an automatic flushing device for an electronic bidet, in which the automatic flushing device has an automatic flushing function and is for both a water tank toilet and a direct flush valve toilet. In contrast to existing bidets, which are produced separately for the water tank toilet and the direct flush valve toilet in order to enable the automatic flushing function of the water tank toilet and the direct flush valve toilet, the automatic flushing device for the electronic bidet enables a single bidet to be capable of being used in both the water tank toilet and the direct flush valve toilet.