A torque wrench has a lock device, which includes a locking sleeve, a restoring elastic member, a clamping member, a locking hole, a locking member, and a positioning assembly. The locking sleeve is provided with an accommodating recess, an abutting portion, and a positioning recess. When the lock device is in a lock position, the locking member is pushed by the abutting portion and pressed against a hollow shank to restrict a handle from rotating relative to the hollow shank. When the lock device is in an unlock position, the locking member is detached from the abutting portion, so that the handle is rotatable relative to the hollow shank.