To provide an easy-to-use electric chainsaw that uses, in place of a large battery pack with a high voltage rating that would have been used in conventional electric chainsaws, a battery power source composed of a set of small commonly used battery packs of the same rating. An electric chainsaw having a built-in electric motor that is powered by a rechargeable battery, wherein a set of commonly used battery packs of the same rating is used as the rechargeable battery. The set of battery packs is mounted at the back of the main housing so that the center of gravity (G) of the chainsaw is positioned within a range (R) of 1.5 time the width (W) of the grip section of a rear handle between the left and right sides of a center line that is centered in the horizontal direction.