Object of the invention is to improve the operability of vertical movement of a portable work machine including a handle without deteriorating the operability of rightward and leftward movement thereof. An enlarged head (42) of a right grip includes an outward enlarged portion (46) that is enlarged rightward, and a lower surface (46a) thereof is composed of an inclined surface having an elevation angle toward a front side. A rear portion (42c) in an upper surface of the enlarged head (42) is composed of a relatively flat surface inclined diagonally downward toward a rear side. In accordance with the configuration, a cutting blade (4) can be moved up and down by using the forefinger and the thumb of a right hand gripping a grip section (40) of the right grip (20).
