The portable belt grinder 201 comprises; a main body 202 with an electric motor 203 built therein; a drive pulley disposed in the lower portion of the main body 202 and rotationally drivable by the electric motor 203; an idle pulley disposed as the companion to the drive pulley; and, an endless abrasive belt 215 wound between the two pulleys. In the portable belt grinder 201, in the portion of the main body 202 that exists in the vicinity of the abrasive belt 215, there is formed a hole portion 202f which is used to visually confirm the side end edge of the abrasive belt 215 from above. Also, on the upper surface of the main body 202, there is mounted a transparent cover 222 which is used to cover the hole portion 202f.