To measure the velocity of flow with accuracy through the use of a sensor chip with a large number of output terminals.

Lead pins are installed in an electrically-connected state to the land part for connecting lead pins of the sensor mounting plate 11 of a sensor unit 10. The installation recessed part 23 of a sensor supporting member is engaged with the sensor mounting plate 11 in a state that the lead pins are inserted through through holes 24 for lead pins to support the sensor unit 10 to a predetermined direction. As a sealing part secures the hermeticity between the sensor unit and sensor supporting member and prevents a fluid from leaking, it is possible to perform accurate measurements and to relax restrictions for installing lead pins. As a result, it is possible to perform a variety of measurements through the use of the sensor main body with a large number of output terminals.