NOVELTY - A polyimide precursor has a repeating unit (X) (I) containing component (A). The component (A) has 2 or more repeating units (II)-(IV). The amount of component (A) contained in the repeating unit (X) is more than 50 mol% with respect to 100 mol% of total amount of the repeating unit (X). A polyimide and polyimide film having thickness of 10 mu m obtained using the polyimide precursor has linear thermal expansion coefficient of 50 ppm/K or less at 50-200 degrees C, and transmittance of 75% or more at wavelength of 400 nm, respectively.    USE - Polyimide precursor is used for formation of polyimide used for varnish used for manufacture of polyimide film of substrate used in touchscreen, solar cell, and display device (all claimed) e.g. liquid crystal display device and electroluminescent device, and transistor and color filter.    ADVANTAGE - The polyimide precursor has excellent heat resistance and bending tolerance, and provides the polyimide film with excellent transparency and reduced linear thermal expansion coefficient.    DETAILED DESCRIPTION - A polyimide precursor has a repeating unit (X) of formula (I) containing component (A). The component (A) has 2 or more repeating units of formulae (II)-(IV). The amount of component (A) contained in the repeating unit (X) is more than 50 mol% with respect to 100 mol% of total amount of the repeating unit (X). A polyimide and polyimide film having thickness of 10 mu m obtained using the polyimide precursor has linear thermal expansion coefficient of 50 ppm/K or less at 50-200 degrees C, and transmittance of 75% or more at wavelength of 400 nm.    A=bivalent group excluding amino group from aromatic diamine or aliphatic diamine;and    X1,X2=hydrogen, 1-6C alkyl, or 3-9C alkylsilyl.    INDEPENDENT CLAIMS are included for the following:    (1) polyimide, which consists of a repeating unit (Y) of formula (VI). The repeating unit (Y) has a component (B) containing 2 or more repeating units;    (2) varnish, which contains the polyimide precursor or the polyimide;    (3) polyimide film, which is obtained using the varnish; and    (4) substrate, which consists of the polyimide film.