To attain sensitivity not deviating in any of XYZ directions. A three-axis antenna with a cross-shaped core 2 having a pair of X-axis arms 22a, 22b projecting in the X-axis direction in an orthogonal coordinate system and a pair of Y-axis arms 23a, 23b projecting in the Y-axis direction orthogonal to aforementioned X-axis direction, and having Z-axis winding wire 26 provided in a substantially rectangular frame shape outside the head sections of aforementioned X-axis arms 22a, 22b and the head sections of aforementioned Y-axis arms 23a, 23b. Aforementioned Z-axis winding wire is housed in a case having a bottom so as to cover the entire head surfaces of X-axis arms 22a, 23b and head surfaces of Y-axis arms 23a, 23b in aforementioned cross-shaped core 2.