A sealing device provided to a joint section of a robot. The sealing device includes overlapped seal portions having a multi-stage configuration, provided for a driving mechanism incorporated into the joint section. The overlapped seal portions include a first seal portion including a first contact seal element sealing a first inter-member gap defined adjacent to a lubricant retaining section provided in the driving mechanism; and a second seal portion arranged outside the first seal portion and including a second contact seal element sealing a second inter-member gap defined in a circumferential wall of the joint section, the circumferential wall defining an accommodation space for accommodating the driving mechanism.