An embodiment relates to a chemical spill preventing device comprising: an end cap member disposed to be able to seal an outlet end of a sampling line through which a chemical is discharged; and a movement unit for selectively moving the end cap member so that the end cap member is positioned at a first position for sealing the outlet end or a second position for opening the outlet end, whereby an advantageous effect of preventing a chemical spill and improving safety and reliability can be obtained.