Aerosol-generating device including sensor to detect color information of an aerosol-generating member

An aerosol-generating device comprising:

• an elongated container comprising an inner wall and an outer wall, wherein the inner wall defines an insert space configured to accommodate insertion of an aerosol-generating member, and wherein a chamber configured to store liquid is defined between the inner wall and the outer wall;
• a wick disposed at an end of the insert space;
• a heater configured to heat the wick;
• a passage formed between the insert space and the wick;
• and
• a sensor disposed adjacent to the insert space and configured to obtain color information about the aerosol-generating member inserted in the insert space,
• wherein the sensor is disposed to face the outer wall and the insertion space where the aerosol-generating member is inserted, and
• wherein each of the outer wall and the inner wall comprises a light-permeable material.