The invention relates to a device for temperature controlled heating of a fluid line which comprises a jacket conduit made of a flexible material and provided with a longitudinal slot across which a fluid line is insertable into a cavity of said jacket conduit, at least one heating element extending in longitudinal direction of said jacket conduit and one temperature sensor each arranged in a first and a second section of the jacket conduit, wherein at both sides of a longitudinal center plane (M) extending through the longitudinal slot (5) the jacket conduit (1, 21) is provided with at least one circumferential section (7, 8, 22, 23) having a plurality of continuous longitudinal channels (9, 9′, 10, 10′, 13, 13′, 13″, 26, 26′) and/or intermittent longitudinal channels (13, 13′, 13″) adapted to accommodate at least two heating elements (11) and/or at least one temperature sensor (14, 15), said continuous longitudinal channels (9, 9′, 10, 10′, 13, 13′, 13″, 26, 26′) and/or intermittent longitudinal channels (13, 13′, 13″) extending symmetrically to said longitudinal center plane (M) of the jacket conduit (1, 21) and/or to a center plane of said circumferential section (7, 8, 22, 23).