A sensor device includes a housing that has a sensor element inserted therein and holds the sensor element such that a detection unit is positioned at the tip end thereof in the axial direction, and an element cover disposed coaxially with the tip end. A tip surface of the outer cover has a plurality of outer tip surface holes provided outward from positions opposing the outer periphery of an inner tip surface hole. The tip surface of the outer cover includes a central portion which protrudes towards the inner tip surface hole, an outer peripheral portion in which the outer tip surface holes are formed and which is positioned farther toward the tip end than is the central portion, and an inclined surface connects the central portion to the outer tip surface holes.