Contact-state of a tire obtaining apparatus and tire-deformation detecting apparatus

A contact-state obtaining apparatus for obtaining a contact state in which a tire (40) of a wheel (2, 4, 6, 8) of a vehicle contacts a road surface, the apparatus comprising a deformation detecting device (32; 130-136; 200; 300) which is supported by the wheel and which detects a deformation of the tire that is caused by a force exerted to the tire in a direction parallel to the road surface; and a contact-state obtaining portion (18) which obtains, as the contact state, (a) a slipping state of the tire relative to the road surface and/or (b) the force exerted to the tire in the direction parallel to the road surface, based on the deformation of the tire detected by the deformation detecting device.