A thermal image generating apparatus for generating a thermal image regarding a target object is provided. The apparatus includes a memory configured to store a first thermal image, a first sensor, configured to measure a temperature of the target object, a second sensor configured to measure a distance to the target object, a third sensor configured to detect a movement of the thermal image generating apparatus, and a controller configured to generate a second thermal image based on temperature information received from the first sensor, distance information received from the second sensor, and movement information received from the third sensor, and generate a third thermal image based on the first thermal image and the second thermal image.