An antifouling composition comprising the following components (A) to (D) and satisfying the following conditions (I) and (II): Component (A): a tetrafunctional silane-based compound represented by the following general formula (a): Si(OR 1 ) p (X 1 ) 4-p (a) wherein, R 1 represents an alkyl group having 1 to 6 carbon atoms; X 1 represents a halogen atom; when plural R 1 s and X 1 s are present, the plural R 1 s and X 1 s may be the same as or different from each other; and p represents an integer of 0 to 4, Component (B): a trifunctional silane-based compound represented by the following general formula (b): R 2 Si(OR 3 ) q (X 2 ) 3-q (b) wherein, R 2 represents an alkyl group having 6 to 14 carbon atoms; R 3 represents an alkyl group having 1 to 6 carbon atoms; X 2 represents a halogen atom; when plural R 3 s and X 2 s are present, the plural R 3 s and X 2 s may be the same as or different from each other; and q represents an integer of 0 to 3, Component (C): a trifunctional silane-based compound represented by the following general formula (c): R 4 Si(OR 5 ) r (X 3 ) 3-r (c) wherein, R 4 represents an alkyl group having 1 to 3 carbon atoms; R 5 represents an alkyl group having 1 to 6 carbon atoms; X 3 represents a halogen atom; when plural R 5 s and X 3 s are present, the plural R 5 s and X 3 s may be the same as or different from each other; and r represents an integer of 0 to 3, Component (D): a metal catalyst, Condition (I): a ratio of a molar amount of the component (A) to a molar amount of the component (B) [(A)/(B)] (molar ratio) is 1.4 or more, and Condition (II): a ratio of a molar amount of the component (B) to a total molar amount of the component (B) and the component (C) [(B)/{(B) + (C)}] (molar ratio) is 0.020 or more. Component (A): a tetrafunctional silane-based compound represented by the following general formula (a): Si(OR 1 ) p (X 1 ) 4-p (a) wherein, R 1 represents an alkyl group having 1 to 6 carbon atoms; X 1 represents a halogen atom; when plural R 1 s and X 1 s are present, the plural R 1 s and X 1 s may be the same as or different from each other; and p represents an integer of 0 to 4, Component (B): a trifunctional silane-based compound represented by the following general formula (b): R 2 Si(OR 3 ) q (X 2 ) 3-q (b) wherein, R 2 represents an alkyl group having 6 to 14 carbon atoms; R 3 represents an alkyl group having 1 to 6 carbon atoms; X 2 represents a halogen atom; when plural R 3 s and X 2 s are present, the plural R 3 s and X 2 s may be the same as or different from each other; and q represents an integer of 0 to 3, Component (C): a trifunctional silane-based compound represented by the following general formula (c): R 4 Si(OR 5 ) r (X 3 ) 3-r (c) wherein, R 4 represents an alkyl group having 1 to 3 carbon atoms; R 5 represents an alkyl group having 1 to 6 carbon atoms; X 3 represents a halogen atom; when plural R 5 s and X 3 s are present, the plural R 5 s and X 3 s may be the same as or different from each other; and r represents an integer of 0 to 3, Component (D): a metal catalyst, Condition (I): a ratio of a molar amount of the component (A) to a molar amount of the component (B) [(A)/(B)] (molar ratio) is 1.4 or more, and Condition (II): a ratio of a molar amount of the component (B) to a total molar amount of the component (B) and the component (C) [(B)/{(B) + (C)}] (molar ratio) is 0.020 or more. <EOS>