To provide an internal pressure measuring apparatus suited for measuring the internal pressure of a compact food container, in which food items and drink are filled and sealed, by restraining the dispersion of the pressure of air by the diffusion of gas flow rate.

A needle section 31 and a sensor section 34 of the internal pressure measuring apparatus 30 are composed so that the flow rate of gas, flowing from the inside of the container to the internal pressure measuring apparatus 30, is smaller than that existing gas flow rate in the vacuum region inside the container. Especially, by reducing a dead volume section (including a conduction region 38), in which a gas flow flows to the sensor section 34, the suppression effect of the dispersion of pressure in the gas flow can be enhanced.