MEASURING INSTRUMENT, MEASURING SYSTEM, AND MEASURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a measuring instrument capable of being easily attached to an internal combustion engine.SOLUTION: A measuring instrument 30 includes: a container 31 for measurement, in which a measurement object chamber 34 subject to inflow of measurement object gas and an introduction passage for introducing the measurement object gas into the measurement object chamber 34 are formed; and a connection structure 32 that connects the introduction passage to a plug hole 25 in a state in which a plug is not attached in an internal combustion engine 20 having the plug hole 25 opened in a combustion chamber 24.