Abstract: A reaction force applying part 5 includes an abutting part (20) provided in one of a moving part (3) and a footrest part (4) and having a first abutting surface (21) and a second abutting surface (22) arranged in a Y direction, a following part (30) provided in the other of the moving part (3) and the footrest part (4) and configured to follow a first rotation operation A of the footrest member (12) and relatively move along the first abutting surface (21) and the second abutting surface (22) while abutting on the first abutting surface (21) and the second abutting surface (22), and a biasing member (40) configured to cause a biasing force to act between the following part (30) and the first abutting surface (21), and between the following part 30 and the second abutting surface (22).