A surge current detection device 30 is detachably attached to a conductor 11 and detects a surge current entering the conductor 11. The surge current detection device 30 includes: a holder 40 releasably holding the conductor 11 via first and second holder bodies 40-1 and 40-2 facing each other; a magnetic force concentrating member 60 having a substantially U-shaped cross-section, the magnetic force concentrating member 60 being secured inside the holder 40 and concentrating a magnetic flux included in a magnetic field generated by the surge current entering the magnetic flux conductor 11 to a high density at a predetermined detection region; and a magnetic material sheet 70 secured inside the holder 40 in such a manner that the magnetic material sheet 70 is positioned at the detection region, the magnetic material sheet 70 detecting the surge current.