We have developed a new torque magnetometer on the basis of a 4-K refrigerator. The system temperature can be lowered down to 1.5 K by pumping liquefied helium from a top loading sample space. A piezoresistor bridge on a Si cantilever is used to detect torque acting on a sample. A transverse magnetic field is supplied by a variable-field permanent magnet up to 10 kG. We find that a sensitivity of our torque magnetometer is Δ τ 10-10 Nm.