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 including a magnet block fixed in position to the housing; a collector unit including a collector disposed between the input shaft and the magnet block and between the output shaft and the magnet block in the radial directions of the input shaft and the output shaft to be partially rotatably connected to each of the input shaft and the output shaft, the collector focusing a magnetic field generated from the magnet unit; and a sensing unit including a torque sensor disposed at the outer circumference of the collector unit and detecting the magnetic field focused by the collector unit.