A device and a method that permit easy and accurate determination of a walking condition regardless of differences in foot landing points on soles or lengths of legs of a walker are provided. According to this device, a measuring device measures a parameter indicating a displacement amount of a bottom end portion of a leg of the walker. A first storage device stores patterns of plots in a determination space corresponding to parameters and walking conditions of the walker such that they are associated with each other. Furthermore, a generating device generates plots defined in the determination space by parameters measured by the measuring device. Then, a determining device determines walking conditions of the walker on the basis of the patterns of the plots stored in conjunction with the walking conditions by the first storage device and the patterns of the plots generated by the generating device.