A 3-axis straight-line motion stage and a sample test device using the same for supporting a predetermined sample, and comprising X-axis, Y-axis and Z-axis stages for moving the sample independently and precisely in the direction of the X-axis, the Y-axis or the Z-axis of rectangular coordinates. The 3-axis straight-line motion stage comprises a bottom plate 40 having a predetermined area and thickness; a X-axis stage 10 fixed in a reference area RR of the bottom plate 40 for moving in the direction of the X-axis a first X area RX1 positioned from the reference RR to the direction of the X-axis; a Y-axis stage 20 positioned within the first X area RX1 and fixed in a second X area RX2, which is located within the first X area RX1 for moving in the direction of the Y-axis a second Y area RY1 positioned from the second X area to the direction of the Y-axis; and a Z-axis stage 30 fixed in the second Y area RY2, which is located within the first Y area RY1 and supporting a predetermined sample for moving the sample in the direction of the Z-axis.