A torque detection device includes a first magnetic circuit part, a second magnetic circuit part, a circuit board module, and a sensor housing. The first magnetic circuit part is disposed on one side of a multipolar magnet in an axial direction. The second magnetic circuit part is disposed on the other side of the multipolar magnet in the axial direction. The circuit board module includes plural magnetic sensors mounted thereon and facing the magnetic circuit on one end side in a width direction being included in the plane and intersecting the arrangement direction. The sensor housing is coupled to one end side in the arrangement direction of the circuit board module so as to support the circuit board module on the one end side in the arrangement direction of the circuit board module.