A line image forming method includes the steps of: ejecting a plurality of droplets of liquid sequentially from an inkjet head, the liquid containing a functional component; and depositing the droplets of the liquid onto a non-permeable medium, the deposited droplets becoming joined together on the non-permeable medium to form a line pattern of the liquid, wherein a receding contact angle of the liquid with respect to the non-permeable medium being not larger than 10°.