The bright-rimmed molecular cloud around S140 IRS has been mapped in the CS (J= 1-0) emission with an angular resolution of 33 arcsec. The relation between the CS emission and the distance from the ionization front is discussed, based on the position of the optical rim determined from an H-alpha photograph. The CS intensity decreases rapidly like a step function toward the rim. The step lies 40 arcsec away from the optical rim. The distribution of the CS emission in the vicinity of S140 IRS shows a barlike east-west elongation which is prominent at V(LSR) = -6 km/s, and an arclike structure clearly seen at V(LSR) = -8 km/s.