A polyimide precursor in accordance with the present invention contains amide acid ester units, either imide units or amide acid units, and fluorine atoms bonded to some of these structural units. A polyimide precursor resin composition in accordance with the present invention contains either such a polyimide precursor or resins separately containing the structural units. Polyimide precursors in accordance with the present invention and resin compositions based on the same therefore have excellent properties and are suitably used in particular to form a particular pattern and for other purposes by impart photosensitivity to them.