A thermosetting silicon-containing film-forming composition for forming a silicon-containing film to be formed in a multi-layer resist process used in lithography, wherein the composition comprises at least: a silicon-containing compound obtained by hydrolysis-condensation of one, or two or more kinds of a hydrolyzable silicon compound represented by the following general formula and one, or two or more compounds selected from the group consisting of a hydrolyzable silicon compound represented by the following general formula and a reactive compound represented by the following general formula, R 1 m1 Si(OR 2) (4-m1) R 3 m3 Si(OR 4) (4-m3) U(OR 5) m5 (OR 6) m6 m7/2 wherein R 1 represents a monovalent organic group substituted with one or more fluorine atoms and having 1 to 30 carbon atoms; R 3 represents a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms, wherein R 1 and R 3 may be the same or different with each other; R 2 and R 4 represent an alkyl group having 1 to 6 carbon atoms; m1 and m3 are integers satisfying m1≤3 and 0≤m3≤3, respectively; R 5 and R 6 represent an organic group having 1 to 30 carbon atoms; m5+m6+m7/2 is a valency determined by the kind of U; each of m5, m6, and m7 is an integer of 0 or more; and U is any element belonging to the groups of III, IV, or V in the periodic table, except for carbon and silicon, one, or two or more kinds of a thermal crosslinking accelerator represented by the following general formula or, L a H b X wherein L represents any of lithium, sodium, potassium, rubidium, and cesium; X represents a hydroxyl group or an organic acid group with one, or two or more valency having 1 to 30 carbon atoms; a represents an integer of 1 or more, b represents 0 or an integer of 1 or more, and a+b is a valency of the hydroxyl group or the organic acid group, M a' H b' A wherein M represents any of a sulfonium group, an iodonium group, and an ammonium group; A represents a hydroxyl group, or an organic acid group with one, or two or more valency having 1 to 30 carbon atoms, or an non-nucleophilic counter ion; a' represents an integer of 1 or more, b' represents 0 or an integer of 1 or more, and a'+b' is a valency of the hydroxyl group, the organic acid group, or the non-nucleophilic counter ion, an organic acid with one, or two or more valency having 1 to 30 carbon atoms, and an organic solvent. a silicon-containing compound obtained by hydrolysis-condensation of one, or two or more kinds of a hydrolyzable silicon compound represented by the following general formula and one, or two or more compounds selected from the group consisting of a hydrolyzable silicon compound represented by the following general formula and a reactive compound represented by the following general formula, R 1 m1 Si(OR 2) (4-m1) R 3 m3 Si(OR 4) (4-m3) U(OR 5) m5 (OR 6) m6 m7/2 wherein R 1 represents a monovalent organic group substituted with one or more fluorine atoms and having 1 to 30 carbon atoms; R 3 represents a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms, wherein R 1 and R 3 may be the same or different with each other; R 2 and R 4 represent an alkyl group having 1 to 6 carbon atoms; m1 and m3 are integers satisfying m1≤3 and 0≤m3≤3, respectively; R 5 and R 6 represent an organic group having 1 to 30 carbon atoms; m5+m6+m7/2 is a valency determined by the kind of U; each of m5, m6, and m7 is an integer of 0 or more; and U is any element belonging to the groups of III, IV, or V in the periodic table, except for carbon and silicon, one, or two or more kinds of a thermal crosslinking accelerator represented by the following general formula or, L a H b X wherein L represents any of lithium, sodium, potassium, rubidium, and cesium; X represents a hydroxyl group or an organic acid group with one, or two or more valency having 1 to 30 carbon atoms; a represents an integer of 1 or more, b represents 0 or an integer of 1 or more, and a+b is a valency of the hydroxyl group or the organic acid group, M a' H b' A wherein M represents any of a sulfonium group, an iodonium group, and an ammonium group; A represents a hydroxyl group, or an organic acid group with one, or two or more valency having 1 to 30 carbon atoms, or an non-nucleophilic counter ion; a' represents an integer of 1 or more, b' represents 0 or an integer of 1 or more, and a'+b' is a valency of the hydroxyl group, the organic acid group, or the non-nucleophilic counter ion, an organic acid with one, or two or more valency having 1 to 30 carbon atoms, and an organic solvent.