A robot having joint shaft that includes: a first-link member and a second-link that are coupled about a rotation axis; a reducer that has an input-shaft fixed to the first-link and an output-shaft fixed to the second-link; a motor that generates a driving force to be input to the reducer; and an input-side encoder and an output-side encoder. The motor is away from the rotation axis, and a power transmission mechanism is provided between the motor and the reducer. The reducer includes a hollow-part and a tubular-member. The tubular-member passes through the hollow-part, one end of which is fixed to the input-shaft or the output-shaft, and the other end of which protrudes from the input-shaft or the output-shaft. The output-side encoder includes a scale and a sensor. The scale is fixed to the tubular-member; and the sensor is fixed to the input-shaft or the output-shaft.