To miniaturize a pressure detecting device detecting the pressure of a sucker for sucking and conveying a work.

This pressure detecting device is fitted to a conveying head provided with the sucker sucking the work. A sensor case 32 is fitted to a passage switching unit provided on the conveying head, and a sensor package 36 is provided in the sensor case 32. An IC chip 42 provided with a signal processing circuit processing the output signal from a pressure sensor provided in the sensor package 36 is fitted to a sensor substrate 35 by flip chip mounting, and the sensor package 36 is fitted to the sensor substrate 35 to cover the IC chip 42. The pressure state of the sucker is lighted and displayed by an LED(light emitting diode) provided on the sensor substrate 35 based on the signal from the pressure sensor.