To provide a ladder truck guidance supporting device with which a proper stop positioning range of a ladder truck corresponding to a selected fire exit or window can be calculated and displayed for workers.

This device is composed of a measuring means 100 for measuring the direction and distance from the top end of a ladder truck to a target point, a target position calculating means 104 for calculating the target position for the top end of the ladder truck to reach based on the direction and distance measured by this measuring means 100, a proper range calculating means 102 for calculating the stop range of the ladder truck by referring to the use limit of the ladder truck from the target position, which is calculated by this target position calculating means 104, for the top end of the ladder truck to reach and a display means 103 for displaying the stop range calculated by this proper range calculating means.