A non-contact current sensor includes a spin valve structure (2), an electrical unit (4) that applies a varying current to the spin valve structure (2), and a resistance reading unit that electrically reads out a resistance value of the spin valve structure (2). When a current-induced magnetic field is detected, a coercive force of a free layer (14) is configured to be larger than the current-induced magnetic field as a detection target, and the electrical unit (4) allows the magnetization directions of a pinned layer (12) and the free layer (14) to transition between a mutually parallel state and a mutually anti-parallel state by applying the current to the spin valve structure (2). The resistance reading unit (5) detects a threshold value corresponding to the transition.