Abstract: The present invention relates to a kind of assembled type mousetrap device, which comprises: a boxlike body having one front opening and one rear opening respectively; a trapdoor having one elastic mechanism and one primary assembly component, wherein, the elastic mechanism can urge the trapdoor to automatically resume its closed position after opening, and the trapdoor may be combined with the front opening of the boxlike body via the primary assembly component with the assembly means; moreover, there is one interlocking mechanism connected to the trapdoor that can be used to restrain the trapdoor from its closing position and thereby sustaining its opening status thereof, and additionally, the restraining function of the interlocking mechanism with regard to the trapdoor can be released by the external force; a back cover having one secondary assembly component, in which, the back cover may be combined with the rear opening of the boxlike body via the secondary assembly component with the assembly means; he