Abstract: Disclosed herein are recombinant cell lines harboring therein an exogenous luciferase gene, in particular transfected mouse hepatoma cell lines Hepa1c1c7-M4P2 and Hepa1c1c7-MP, in which a DNA fragment having nucleotide sequences “cacgc” and “gcgtg” that may be specifically present in dioxin-response elements is located upstream of the luciferase gene, the DNA fragment being designed based on the promoter region and a part of the front sequence of the structure gene of Mus musculus CYP1A1 gene. As such, the recombinant cell lines and the subcultured offsprings thereof can be used via bioassay for the detection of dioxin-like compounds present in a sample collected from a natural environment, including: soil; water sources; edible meats, fishes, vegetables and fruits and the like; and flues, bottom ashes, sludge or the like in plants or incinerators.