The coastal Aleochara fucicola Sharp species complex include A. fucicola Sharp, A. hayamai Yamamoto and Maruyama, A. puetzi (Assing), and A. segregata Yamamoto and Maruyama. To clarify the delineation and phylogenetic relationships of the A. fucicola species complex, we conducted phylogenetic analyses based on molecular characters and detailed morphological characters by using scanning electron microscopy (SEM) images. The dataset comprised two mitochondrial (cytochrome c oxidase I and COII) and three nuclear protein coding genes (CAD, EF1-a, and Wingless) for 34 populations of four species of A. fucicola species complex. We found strong disagreement between mitochondrial and nuclear gene trees. Two species, A. puetzi and A. segregata, were not distinguished by mitochondrial DNA data, but distinguished by nuclear DNA data and SEM characters. A multilocus phylogeny and SEM images revealed four well-supported species lineages. Based on a multicolus phylogeny and SEM images, we conclude the following the taxonomic status of the Aleochara fucicola species complex with four species (A. fucicola, A. hayamai, A. puetzi, and A. segregata).