A sensor device includes a resin inner housing which has an accommodating space therein and in which an opening is provided, an externally exposed part which is disposed to cover the opening or pass through the opening and of which at least a part is exposed to the outside of the inner housing, and a metal outer housing which is positioned outside the inner housing and accommodates the inner housing and covers the inner housing. When a sealing treatment is performed between the inner housing and the externally exposed part, the accommodating space is sealed off from a space outside the inner housing. When a cut-off part is provided in the outer housing at a position corresponding to the part exposed to the outside of the inner housing of the externally exposed part, the part of the externally exposed part is also exposed to the outside of the outer housing.