An injector includes a nozzle body, a main body including a supply port on the outer peripheral surface of the main body and a high pressure passage, and a fuel pressure sensor on an outer peripheral surface of the main body to detect fuel pressure. The high pressure passage has a first passage extending from the supply port in a radial direction of the main body, and a second passage extending from a fuel downstream end portion of the first passage toward an injection hole in an insertion direction of the nozzle body. The supply port and the sensor are diametrically opposed to each other. The main body includes a sensor passage, which branches from the high pressure passage to extend from the fuel downstream end portion of the first passage in an imaginary extension of the first passage so that fuel flows into the sensor through the sensor passage.