A head space sample introduction device comprising: a sample container; a sample gas passage connected to a head space of the sample container, the head space for storing a sample gas generated from a sample; a pressurization gas supply source of a constant first pressure larger than atmospheric pressure; a first pressurization passage connected to the pressurization gas supply source of a constant first pressure larger than atmospheric pressure; a sample loop for collecting the sample gas; a discharge passage for discharging the sample gas; a carrier gas passage for supplying a carrier gas; an analysis passage configured to be connected to an analyzer; a passage switching mechanism (10,14,24) for switching among a head space pressurization passage configuration in which the first pressurization passage is connected to the head space, a sample gas collection passage configuration in which the sample loop is connected between the sample gas passage and the discharge passage, and a sample gas introduction passage configuration in which the sample loop is connected between the carrier gas passage and the analysis passage; and a pressurization gas supply source of a constant second pressure larger than atmospheric pressure; a second pressurization passage including: a first resistance pipe having one end connected to a downstream side of the discharge passage and the other end exposed to the atmosphere; and a second resistance pipe having one end connected to the downstream side of the discharge passage and the other end connected to the pressurization gas supply source of a constant second pressure larger than atmospheric pressure characterized in that in use the second pressurization passage applies to the discharge passage a constant pressure larger than atmospheric pressure obtained by dividing the second pressure with the first and second resistance pipes (28, 30). a sample container; a sample gas passage connected to a head space of the sample container, the head space for storing a sample gas generated from a sample; a pressurization gas supply source of a constant first pressure larger than atmospheric pressure; a first pressurization passage connected to the pressurization gas supply source of a constant first pressure larger than atmospheric pressure; a sample loop for collecting the sample gas; a discharge passage for discharging the sample gas; a carrier gas passage for supplying a carrier gas; an analysis passage configured to be connected to an analyzer; a passage switching mechanism (10,14,24) for switching among a head space pressurization passage configuration in which the first pressurization passage is connected to the head space, a sample gas collection passage configuration in which the sample loop is connected between the sample gas passage and the discharge passage, and a sample gas introduction passage configuration in which the sample loop is connected between the carrier gas passage and the analysis passage; and a pressurization gas supply source of a constant second pressure larger than atmospheric pressure; a second pressurization passage including: a first resistance pipe having one end connected to a downstream side of the discharge passage and the other end exposed to the atmosphere; and a second resistance pipe having one end connected to the downstream side of the discharge passage and the other end connected to the pressurization gas supply source of a constant second pressure larger than atmospheric pressure characterized in that in use the second pressurization passage applies to the discharge passage a constant pressure larger than atmospheric pressure obtained by dividing the second pressure with the first and second resistance pipes (28, 30). a first resistance pipe having one end connected to a downstream side of the discharge passage and the other end exposed to the atmosphere; and a second resistance pipe having one end connected to the downstream side of the discharge passage and the other end connected to the pressurization gas supply source of a constant second pressure larger than atmospheric pressure characterized in that in use the second pressurization passage applies to the discharge passage a constant pressure larger than atmospheric pressure obtained by dividing the second pressure with the first and second resistance pipes (28, 30).