To provide a telescopic device, capable of extending/contracting a plurality of arms by a single drive part to achieve compactness.

This telescopic device 1 is mainly composed of a rail 3 disposed in the horizontal direction, a base 4 installed on the rail 3, a first arm 5 that is long, and longitudinally disposed roughly vertically along the base 4, the drive part 6 installed on the base 4, and connected to the first arm 5, a second arm 7 that is long, and longitudinally disposed roughly vertically along the first arm 5, a third arm 8 that is long, and longitudinally disposed roughly vertically along the second arm 7, a first slide means to longitudinally slidably support the first arm 5 to the base 4, a second slide means to longitudinally slidably support the second arm 7 to the first arm 5, and an interlock means interlocked with sliding of the first arm 5 by the drive part 6 to slide the second arm 7 in the same direction as the first arm 5.