Chair, in particular an office chair comprising a) a foot frame, b) a seat support connected to the foot frame, c) a seat mounted on the seat support which seat can be adjusted in its inclination between a lower position and an upper position, and d) a seat inclination adjusting device for adjusting the inclination of the seat between the lower position and the upper position, comprising i) an actuatable activating rod, which - is mounted rotatably on the seat support, and - comprises at least one activating rod thread (32, 33), and ii) at least one adjusting slide displaceable by rotating the activating rod, which comprises - at least one adjusting part engaging on the seat for adjusting the inclination of the seat, and - an adjusting slide thread in engagement with the at least one activating rod thread (32, 33) for its displacement along the activating rod, iii) wherein the seat inclination adjusting device is designed such that the seat can be adjusted on the one hand into an upper position by rotating the activating rod, characterised in that e) the seat can be adjusted on the other hand into the upper position by applying a manual, upwardly directed adjusting force directly to the seat, and f) the at least one activating rod thread (32, 33) and/or adjusting slide thread is not self-locking. a) a foot frame, b) a seat support connected to the foot frame, c) a seat mounted on the seat support which seat can be adjusted in its inclination between a lower position and an upper position, and d) a seat inclination adjusting device for adjusting the inclination of the seat between the lower position and the upper position, comprising i) an actuatable activating rod, which - is mounted rotatably on the seat support, and - comprises at least one activating rod thread (32, 33), and ii) at least one adjusting slide displaceable by rotating the activating rod, which comprises - at least one adjusting part engaging on the seat for adjusting the inclination of the seat, and - an adjusting slide thread in engagement with the at least one activating rod thread (32, 33) for its displacement along the activating rod, iii) wherein the seat inclination adjusting device is designed such that the seat can be adjusted on the one hand into an upper position by rotating the activating rod, i) an actuatable activating rod, which - is mounted rotatably on the seat support, and - comprises at least one activating rod thread (32, 33), and - is mounted rotatably on the seat support, and - comprises at least one activating rod thread (32, 33), and ii) at least one adjusting slide displaceable by rotating the activating rod, which comprises - at least one adjusting part engaging on the seat for adjusting the inclination of the seat, and - an adjusting slide thread in engagement with the at least one activating rod thread (32, 33) for its displacement along the activating rod, - at least one adjusting part engaging on the seat for adjusting the inclination of the seat, and - an adjusting slide thread in engagement with the at least one activating rod thread (32, 33) for its displacement along the activating rod, iii) wherein the seat inclination adjusting device is designed such that the seat can be adjusted on the one hand into an upper position by rotating the activating rod, e) the seat can be adjusted on the other hand into the upper position by applying a manual, upwardly directed adjusting force directly to the seat, and f) the at least one activating rod thread (32, 33) and/or adjusting slide thread is not self-locking.