A tire characteristic judging device judges a tire characteristic in the following way. At first, a load applied to a tire and a cornering force generated in the tire in time series while the tire is rolling are acquired. Then, an applied load variation amount is calculated from the acquired time-series applied load information and a cornering force variation amount calculated from the acquired time-series cornering force information. Next, an evaluation value is calculated based on the applied load variation amount and the cornering force variation amount. The calculated evaluation value and a preset reference value are compared with each other and whether or not the tire satisfies a desired characteristic is judged according to a result of comparison.