Provided is an outdoor sensing device having a structure which can prevent ingress of specific intruding objects, directly drain intruded water and dew inside the main body of the device, and further have enhanced freedom in design without limiting the external design. The outdoor sensing device includes: a functional unit including a sensing element and a processing circuit; a cover unit including an inner cover which has a predetermined dimension and houses the functional unit, and an outer cover which houses the inner cover; and a base unit, wherein the inner cover includes a water ingress prevention structure disposed between the functional unit and the optical member to prevent water ingress from outside of the inner cover, and further includes a drain hole and a guide part configured to guide the water toward the drain hole on a bottom wall of the inner cover, and the outer cover has a bottom wall which defines a predetermined gap with respect to the bottom wall of the inner cover, and the bottom wall of the outer cover includes a drain part configured to drain the water from the drain hole to outside of the outdoor sensing device and includes a blind structure which covers the drain hole of the inner cover such that the drain hole cannot be seen from the outside of the outdoor sensing device when viewed from below.