Abstract: A method of filling a narrow channel having a closed end with liquid comprises: filling the channel with vaporized volatile substance; and filling the channel having been filled with the volatile substance in a gaseous state with injection liquid by applying pressure. In the step of filling the channel with the vaporized volatile substance, air existing inside the channel is discharged to outside of the channel. In the step of filling the channel with the injection liquid, a condensation of the volatile substance in the gaseous state and a phase change into a liquid state occur by the applied pressure, volume of the volatile substance is reduced, and a space inside the channel having been occupied by the volatile substance in the gaseous state is filled with the injection liquid.