A state of a user of a mobile terminal having a display for displaying an image may be estimated. A sightline detector detects a sightline of the user of a mobile terminal and processing circuitry is configured to estimate a state of the user. The processing circuitry is configured to determine a top-down index value that is correlated with an attention source amount allocated to top-down attention of the user with respect to an image displayed on a display of the mobile terminal. The processing circuitry is configured to determine a bottom-up index value correlated with the attention source amount allocated to bottom-up attention of the user with respect to the image displayed on the display. The processing circuitry is configured to estimate the user state including an attention function degraded state based on the top-down index value and the bottom-up index value.