Abstract: To provide an organic synthesizer that can conduct a pressure reaction and an atmospheric reaction in one organic synthesizer and can realize attachment of reaction vessels to the organic synthesizer and detachment of the reaction vessels from the organic synthesizer without applying any load to gas supply/discharge pipes. [MEANS FOR SOLVING PROBLEMS] An organic synthesizer comprising a reaction vessel support part (160), which can support two or more reaction vessels, and pressure regulation means (164) for regulating the pressure within the reaction vessel supported by the reaction vessel support part (160) by supplying/discharging gas. Two or more pressure regulation means (164) are provided for each reaction vessel supported by the reaction vessel support part (160). At least one pressure regulation means (164A) in the two or more pressure regulation means (164) is constructed so as to be detachable from and attachable to the other pressure regulation means (164B).

Abstract: The oscillation of an oscillator is automatically stopped during gas sampling, and the gas sampling is automatically stopped during the measurement of the frequency of the oscillator before and after the gas sampling, thereby making it possible to avoid the measurement error due to a change in resonance frequency by the effect of dynamic and static pressures applied to a filter paper holder mounted at the free end of the oscillator in the gas sampling, and to prevent the dislodgement and reentrainment of suspended particulates collected in the filter paper due to the oscillation acceleration. Accordingly, it is possible to accurately measure the mass of suspended particulates deposited on a filter paper compared with the conventional method in which the gas sampling and the measurement of the frequency are simultaneously and continuously performed while oscillating an oscillator.