Abstract: A posture detection system for detecting a user's posture according to the embodiments includes a pressure sensor unit, a controller, a feedback mechanism, and a display unit. The pressure sensor unit has a sheet shape or a padded shape and includes plurality of sensors. Each of the sensors is configured to detect a pressure applied from the user. The controller is configured to classify the user's posture based on detection data detected by the pressure sensor unit. The feedback mechanism is configured to provide feedback to the user by vibrating based on a result of the classification. The display unit is configured to perform a display according to the result of the classification.