A hair clipper comprising: a blade block; and an adjusting device for adjusting a clipping height of said blade block, said adjusting device comprises: an attachment being disposed to overlap with said blade block and to be allowed to move in a predetermined moving direction relative to said blade block; a handle ring formed into a circular hollow cylindrical shape and disposed to be rotated around a rotation axis extending along the moving direction; and a connection mechanism connecting said handle ring to said attachment such that said attachment is moved with rotation of said handle ring, and the clipping height is determined by a relative position of said attachment to said blade block in the moving direction, said connection mechanism comprises: a cam groove provided to one of said attachment and said handle ring; and a linking pin provided to the other of said attachment and said handle ring, and placed inside said cam groove so as to be moved along said cam groove, and said cam groove includes a first side and a second side opposite to each other in the moving direction, characterized in that said first side includes: plural step parts formed in different positions in the moving direction respectively associated with the different clipping heights; and a slope part configured to connect said step parts, said step parts extend in a direction normal to the moving direction; said second side comprises: plural second step parts respectively opposite to said plural step parts; and a second slope part configured to connect said second step parts, and said cam groove is designed to hold said linking pin between said step part and said second step part opposite thereto. a blade block; and an adjusting device for adjusting a clipping height of said blade block, said adjusting device comprises: an attachment being disposed to overlap with said blade block and to be allowed to move in a predetermined moving direction relative to said blade block; a handle ring formed into a circular hollow cylindrical shape and disposed to be rotated around a rotation axis extending along the moving direction; and a connection mechanism connecting said handle ring to said attachment such that said attachment is moved with rotation of said handle ring, and the clipping height is determined by a relative position of said attachment to said blade block in the moving direction, an attachment being disposed to overlap with said blade block and to be allowed to move in a predetermined moving direction relative to said blade block; a handle ring formed into a circular hollow cylindrical shape and disposed to be rotated around a rotation axis extending along the moving direction; and a connection mechanism connecting said handle ring to said attachment such that said attachment is moved with rotation of said handle ring, and the clipping height is determined by a relative position of said attachment to said blade block in the moving direction, said connection mechanism comprises: a cam groove provided to one of said attachment and said handle ring; and a linking pin provided to the other of said attachment and said handle ring, and placed inside said cam groove so as to be moved along said cam groove, and said cam groove includes a first side and a second side opposite to each other in the moving direction, a cam groove provided to one of said attachment and said handle ring; and a linking pin provided to the other of said attachment and said handle ring, and placed inside said cam groove so as to be moved along said cam groove, and said cam groove includes a first side and a second side opposite to each other in the moving direction, characterized in that said first side includes: plural step parts formed in different positions in the moving direction respectively associated with the different clipping heights; and a slope part configured to connect said step parts, said step parts extend in a direction normal to the moving direction; plural step parts formed in different positions in the moving direction respectively associated with the different clipping heights; and a slope part configured to connect said step parts, said step parts extend in a direction normal to the moving direction; said second side comprises: plural second step parts respectively opposite to said plural step parts; and a second slope part configured to connect said second step parts, and said cam groove is designed to hold said linking pin between said step part and said second step part opposite thereto. plural second step parts respectively opposite to said plural step parts; and a second slope part configured to connect said second step parts, and said cam groove is designed to hold said linking pin between said step part and said second step part opposite thereto.