This invention provides a non-contact temperature-measuring device including a distance sensor unit, an alarm unit, a temperature sensor unit, a microprocessor unit and a display unit. The distance sensor unit measures the distance between the device and a target. The alarm unit gives an alarm when the distance sensor unit measures a predetermined distance value. The temperature sensor unit measures a temperature of the target after the alarm unit gives the alarm. The microprocessor unit stores data of the predetermined distance value and the temperature value measured by the temperature sensor unit; the microprocessor unit also processes a distance signal emitted by the distance sensor unit and a temperature signal emitted by the temperature sensor unit. When the target's distance value equals the predetermined distance value, the microprocessor unit will further send a command for the alarm unit to give an alarm. The display unit of the device displays the temperature value that is measured by the temperature sensor unit and processed by the microprocessor unit subsequently.