To automatically keep the dip of a strung cable from a vehicle mounted cable drum within a specified range.

An equipment is provided with a cable drum 10 for a strung cable 20 installed on an engine-provided vehicle 2; a dip detector 30 for detecting the dip of the strung cable 20 drawn from the cable drum 10; and a cable drum rotating means which uses an engine as a driving source and stops the rotation of the cable drum 10 when the detected dip is a first dip quantity or above, sets the rotating speed of the cable drum 10 to a first speed when the detected dip is larger than a second dip quantity and smaller than the first one, and sets the rotating speed to a second speed faster than the first one when the detected dip is the second dip quantity or below.