A hedge trimmer capable of effectively increasing the rigidity of a cutter assembly as well as reducing its weight, and easily adjusting the clearance for sliding of cutters, thereby improving the operability and addressing degradation of the cutting performance of the cutters is disclosed. In the cutter assembly, upper and lower cutter supports are provided with a plurality of clamping portions at predetermined intervals for increasing the rigidity, each clamping portion having a square tube-like spacer and a first bolt. In addition, at least one adjusting portion having a second bolt for adjusting the separation distance between the upper and lower cutter supports is provided between adjacent clamping portions.