Pressure detection device with detachable temperature reducing buffer member

A pressure detection device 1 includes: an enclosure assembly configured to be mounted in a communication hole in an internal combustion engine; a diaphragm head 32 provided at one end of the enclosure assembly and configured to receive pressure of combustion gas from the internal combustion engine; and a buffer member 80 located at the diaphragm head 32 and configured to supply the combustion gas to the diaphragm head 32 while reducing the temperature of the combustion gas. Female threads formed on a first buffer member 81 of the buffer member 80 and male threads formed on a second buffer member 82 of the buffer member 80 are configured to threadably engage each other.