A planar sensor having a conductor pattern for electric field sensing and its manufacturing method, the planar sensor comprising arrays of planar electrically conductive sensor areas (2) arranged to follow each other in a successive manner along the longitudinal direction, and conductors connecting electrically conductive sensor area to at least one connector, wherein the sensor further comprises a first elastic flooring layer (3) and at least one of the following: a second elastic flooring layer (4) or a flexible circuit board, and the electrically conductive sensor areas (2) and the conductors are attached between the first elastic flooring layer (3) and the second elastic flooring layer (4) or between the first elastic flooring layer (3) and the flexible circuit board to form a unitary floor sensor structure.