A catalyst for preparation of a polyester, comprising a reaction product of: a titanium compound component comprising acetic acid and at least one member selected from titanium compounds represented by the general formula: in which formula, R 1, R 2, R 3 and R 4 respectively and independently from each other represents an alkyl group having 2 to 10 carbon atoms, k represents an integer of 1 to 3 and, when k is 2 or 3, two or three R 2 and R 3 substituents may be the same as or different from each other, and titanium compounds obtained by reacting the titanium compounds of the general formula with aromatic polycarboxylic acids represented by the general formula: in which formula, m represents an integer of 2 to 4, or anhydrides of the acids of the formula; and a phosphorus compound component, characterised in that: the phosphorus compound component comprises at least one member of phosphorus compounds represented by the general formula: in which formula, R 5 represents a non-substituted or substituted aryl group having 6 to 20 carbon atoms, or a non-substituted or substituted alkyl group having 1 to 20 carbon atoms; and in the reaction product of the titanium compound component with the phosphorus compound component, a reaction molar ratio (m Ti /m p) of a molar amount (m Ti), in terms of titanium atoms, of the titanium compound component to a molar amount (m p), in terms of phosphorus atoms, of the phosphorous compound component is within the range from 1:1 to 1:3. a titanium compound component comprising acetic acid and at least one member selected from titanium compounds represented by the general formula: in which formula, R 1, R 2, R 3 and R 4 respectively and independently from each other represents an alkyl group having 2 to 10 carbon atoms, k represents an integer of 1 to 3 and, when k is 2 or 3, two or three R 2 and R 3 substituents may be the same as or different from each other, and titanium compounds obtained by reacting the titanium compounds of the general formula with aromatic polycarboxylic acids represented by the general formula: in which formula, m represents an integer of 2 to 4, or anhydrides of the acids of the formula; and a phosphorus compound component, characterised in that: the phosphorus compound component comprises at least one member of phosphorus compounds represented by the general formula: in which formula, R 5 represents a non-substituted or substituted aryl group having 6 to 20 carbon atoms, or a non-substituted or substituted alkyl group having 1 to 20 carbon atoms; and in the reaction product of the titanium compound component with the phosphorus compound component, a reaction molar ratio (m Ti /m p) of a molar amount (m Ti), in terms of titanium atoms, of the titanium compound component to a molar amount (m p), in terms of phosphorus atoms, of the phosphorous compound component is within the range from 1:1 to 1:3. the phosphorus compound component comprises at least one member of phosphorus compounds represented by the general formula: in which formula, R 5 represents a non-substituted or substituted aryl group having 6 to 20 carbon atoms, or a non-substituted or substituted alkyl group having 1 to 20 carbon atoms; and in the reaction product of the titanium compound component with the phosphorus compound component, a reaction molar ratio (m Ti /m p) of a molar amount (m Ti), in terms of titanium atoms, of the titanium compound component to a molar amount (m p), in terms of phosphorus atoms, of the phosphorous compound component is within the range from 1:1 to 1:3.