A grinder includes a body having an annular portion, a wheel cover which is attachable to the annular portion, and a wheel cover holding member which holds the wheel cover. The wheel cover has a cylindrical portion which is attachable to the annular portion. The wheel cover holding member has a slide member and a pressing portion which moves the slide member. The pressing portion switches a state between an engagement state in which the slide member is engaged with the cylindrical portion and a disengagement state in which the slide member is disengaged with the cylindrical portion by moving the slide member. The pressing member moves on a second line which is parallelly offset from a first line passing the center of the annular portion in a predetermined direction.