The invention provides a support roller of a crawler type traveling apparatus which can prevent a rotational resistance from being increased by the soil or the like, and can stably achieve a function serving as the support roller for a long time. The invention provides a support roller of a crawler type traveling apparatus provided with a shaft (1), a support portion (2) supporting a center portion in an axial direction of the shaft (1), and a pair of rollers (3, 3) respectively arranged in both end portions (1a, 1a) of the shaft (1) and rotating together with the shaft (1). A mounting seat portion (36) of the support portion (2) to a track frame (51) is set within a range (S) of a roller outer shape formed by a pair of rollers (3, 3) in a plan view.