A measuring apparatus includes a light receiving device, a housing, an optical window, an electrical connection line, and a line enclosure. The light receiving device receives light and output a signal. The housing, made of a conductive material, covers the light receiving device. The optical window transmits the light. The optical window includes a conductive part having conductivity. The electrical connection line transmits the signal. The line enclosure is disposed around the electrical connection line and electrically connected to the conductive part and the housing.