Animal trap device

An animal trap device includes a base, circular cover plate, elastic element and elastic lasso; at least two posts are configured on one face of the base, and each post includes a stop; a circular cover plate includes a top portion, a surrounding portion and a flange, where the surrounding portion surrounds the circumference of the top portion, and the flange is projected outward from the surrounding portion and positioned below the stops; the elastic element is configured between the base and the circular cover plate, and adapted to provide the circular cover plate with a upward elastic force; the elastic lasso is wound around the surrounding portion, and positioned above the stops. Whereby, the elastic lasso will be blocked by the stops, not moved downward, and not reduce until leaving the surrounding portion when the circular cover plate is exerted with a force to move downward.