PURPOSE: To provide a means of detecting exact suction air temperature by installing a temperature sensor in the throttle chamber through elastic body of less heat conductivity.

CONSTITUTION: A sensor 1 which converts a temperature to an electric signal is installed in the throttle chamber 2 with a spring 3 and screws 4, leaving a clearance so that the sensor 1 does not touch the chamber 2. Because the sensor 1 is installed through the spring 3 of less heat conductivity, it receives less influence of the temperature of attached members such as suction manifold (not shown in the figure), chamber 2, etc., and is allowed to detect exact suction air temperature, as well as being prevented from destruction caused by over tightening at the time of installation by aid of elastic holding process.