A 3-axis magnetic field sensor on a substrate and including, a first tunneling magneto-resistor (TMR) having a first easy-axis for sensing a X-axis magnetic field, a second TMR having a second easy-axis for sensing a Y-axis magnetic field, an out-of-plane magnetic sensor for sensing a Z-axis magnetic field, and a reference unit is provided. The first easy-axis and the second easy-axis are orthogonal and include an angle of 45±5 degrees with a bisection direction, respectively. The out-of-plane magnetic sensor includes a groove or bulge structure having a first incline and a second incline; a third TMR on the first incline having a third easy-axis; a fourth TMR on the second incline having a fourth easy-axis; and a central axis orthogonal to the bisection direction and parallel to the third easy-axis and the fourth easy-axis. The reference unit has a fifth TMR and a fifth easy-axis parallel to the bisection direction.