PURPOSE: To obtain a differential-pressure transmission apparatus in which a transmission-part side is separated easily from a pressure-receiving-part side in a maintenance and inspection operation or the like by a method wherein a bolt hole is made in an insertion support base which is installed so as to suspend a differential-pressure transmission part and the differential- pressure transmission part is driven so as to be taken in and out by making use of the bolt hole as a guide hole.

CONSTITUTION: In an insertion support base 33 which is installed so as to suspend a differential-pressure transmission part 32, two through holes 2 in which a female screw has been cut are made, on a transmission-part side 1, bolts 3 are inserted into and passed through, and they are tightened by a tool such as a screwdriver or the like. Tip parts 10 of the bolts 3 hit a cylinder part 11 on a pressure-receiving-part side 4. When the bolts 3 are tightened further, the transmission-part side 1 is pushed up. The bolts 3 are used to separate the transmission-part side 1 from the pressure-receiving-part side 4 in a maintenance and inspection operation or the like, and they are removed usually. Consequently, while a pressure and differential-pressure transmission apparatus is operated, the through holes 2 in which the female screw has been cut act to promote heat conduction. When the inside of the transmission-part side 1 generates a temperature difference partly due to a cause from the outside of the transmission-part side 1, the temperature of an amplifier 15 at the inside can be made uniform in a short time by the through holes 2.