Provided is a torque sensor device to detect a torque between an input shaft and an output shaft through a relative rotation displacement therebetween. The torque sensor device includes: a housing to accommodate an end of the input shaft and an end of the output shaft: a magnet unit rotatably accommodated in the housing to be connected to one end of one of the input shaft and the output shaft; a collector unit rotatably accommodated in the housing to be connected to one end of the other of the input shaft and the output shaft, the collector unit forming a magnetic circuit together with the magnet unit; and a sensing unit including a torque sensor disposed at the outer circumference of the collector unit and configured to detect a magnetic field focused by the collector unit. The collector unit includes a lower collector including an annular lower collector ring.