To make it possible for a power chain saw to make use of the type of structure of a machine which is equipped with an upper handle in a machine which is equipped with a rear handle too with a minimum manufacturing cost, and, in this case, to make it possible to apply a maximum number of constitutional groups to both machines.

The handle is disposed as a rear handle 7 which extends in the longitudinal direction of a prime mover casing 1 substantially behind the back side part 9 of the prime mover casing 1, which is opposite to a guide rail 2, the rear handle 7 is fixed to a vibration-proof element 15 in the upper side part 12 with a supporting arm 11 overlapping the prime mover casing 1, and a curved grip 20 overlaps the supporting arm with a space a and is fixed at its first end part 21 to the longitudinal side part of the supporting arm 11, which is opposite to the side wall.