A sensor apparatus includes a first cover member; a detection element including an element substrate located on the first cover member, and a detection portion configured to detect an analyte, the detection portion being located on the element substrate; a terminal located on the first cover member and electrically connected to the detection element; an intermediate cover member located on the first cover member and having a space with the detection element; a filler member located in the space between the detection element and the intermediate cover member; a second cover member configured to cover at least a part of the detection element and joined to at least one of the first cover member and the intermediate cover member; an inlet into which the analyte flows; and a flow passage which is continuous with the inlet, and extends at least to the detection portion.