A reaction force generator includes a hollow elastic member made of an elastically deformable material and a protrusion protruding from an outer surface of the hollow elastic member, the protrusion being tiltable in at least a first direction and a second direction, the first and second direction being symmetric with each other about a neutral position of the protrusion, wherein at least one of physical dimensions and material properties of the hollow elastic member is asymmetric with respect to the neutral position of the protrusion along the first direction and the second direction such that a first reaction force that would be generated by the protrusion when tilted in the first direction and a second reaction force that would be generated by the protrusion when tilted in the second direction are asymmetric with respect to the neutral position of the protrusion.