A magnetic detection device comprising: a substrate (S); and a first magneto-impedance, MI element (M1) disposed at one surface side of the substrate and comprising a first magneto-sensitive wire (W1) and a first detection coil (C1), the first magneto-sensitive wire (W1) sensing an external magnetic field component in a first axis direction in which the first magneto-sensitive wire (W1) extends, the first detection coil (C1) looping around the first magneto-sensitive wire (W1), the first detection coil (C1) comprising a left-side coil part (C11) and a right-side coil part (C12) that coexist along the one continuous first magneto-sensitive wire (W1), the magnetic detection device further comprising a magnetic field direction changing body composed of a soft magnetic material of which at least a part is disposed at another surface side of the substrate (S) or in the substrate (S) above an intermediate position between the left-side coil part (C11) and the right-side coil part (C12), the magnetic field direction changing body (F1) being able to change an external magnetic field component in a third axis direction to a measurement magnetic field having a component in the first axis direction, the third axis direction intersecting the substrate, the external magnetic field component in the third axis direction being able to be detected on a basis of a left-side output (V11) obtained from the left-side coil part (C11) and a right-side output (V12) obtained from the right-side coil part (C12), wherein the magnetic field direction changing body (F1) has a contracted part (F12) at a near side to the first magneto-sensitive wire (W1) and has an expanded part (F11) at a far side from the first magneto-sensitive wire (W1). a substrate (S); and a first magneto-impedance, MI element (M1) disposed at one surface side of the substrate and comprising a first magneto-sensitive wire (W1) and a first detection coil (C1), the first magneto-sensitive wire (W1) sensing an external magnetic field component in a first axis direction in which the first magneto-sensitive wire (W1) extends, the first detection coil (C1) looping around the first magneto-sensitive wire (W1), the first detection coil (C1) comprising a left-side coil part (C11) and a right-side coil part (C12) that coexist along the one continuous first magneto-sensitive wire (W1), the magnetic detection device further comprising a magnetic field direction changing body composed of a soft magnetic material of which at least a part is disposed at another surface side of the substrate (S) or in the substrate (S) above an intermediate position between the left-side coil part (C11) and the right-side coil part (C12), the magnetic field direction changing body (F1) being able to change an external magnetic field component in a third axis direction to a measurement magnetic field having a component in the first axis direction, the third axis direction intersecting the substrate, the external magnetic field component in the third axis direction being able to be detected on a basis of a left-side output (V11) obtained from the left-side coil part (C11) and a right-side output (V12) obtained from the right-side coil part (C12), wherein the magnetic field direction changing body (F1) has a contracted part (F12) at a near side to the first magneto-sensitive wire (W1) and has an expanded part (F11) at a far side from the first magneto-sensitive wire (W1). <EOS>