Provided is a sample loading method of loading a cooled sample into a sample exchange chamber of a charged particle beam apparatus includes: attaching the sample container in which a sample and liquid nitrogen are accommodated to the sample exchange chamber via a gate valve; evacuating a space between a liquid surface of the liquid nitrogen and the gate valve in a state in which the gate valve is closed; discharging the liquid nitrogen in the sample container after the space between the liquid surface of the liquid nitrogen and the gate valve has been evacuated; evacuating a space in the sample container after the liquid nitrogen in the sample container has been discharged; and opening the gate valve after the space in the sample container has been evacuated.