Measurement system and measurement method

A measurement system comprising:

• two earphones which are respectively worn in a left ear and a right ear of a user and in which a plurality of earpieces having different sizes are replaceably attached on one end side of each earphones, and
• a wireless terminal carried by the user, wherein
• the earphone includes a speaker and a microphone, and picks up a sound by the microphone in a case where a currently worn earpiece, which is any of the plurality of earpieces, is worn in the left ear or the right ear of the user and a sound signal transmitted from the wireless terminal or a sound signal output from the earphone is output from the speaker,
• the measurement system executes a measurement process at least once on whether the currently worn earpiece is sealed in the left ear or the right ear of the user based on the picked-up sound signal, and
• the wireless terminal includes a display unit, receives an input operation related to a wearing feeling of the currently worn earpiece worn in the left ear or the right ear of the user, and displays, on the display unit, a notification indicating that a size of the currently worn earpiece worn by the user is a most suitable size among the sizes of the plurality of earpieces, or a notification for prompting replacement with another earpiece having a size larger or smaller than the size of the currently worn earpiece, based on the input operation related to the wearing feeling and a measurement result by the measurement process.