Disclosed is a thietane compound represented by the following general formula (1), (wherein, in the above general formula (1), M represents an element belonging to Group 14 of the Periodic Table in the long form; X1s each independently represent a sulfur atom or an oxygen atom; p represents an integer of equal to or more than 2 and equal to or less than (n−1); and n represents the number of valence of a metal atom M, provided that when n−p is 1, R2 represents an alkyl group having a straight chain or a branched chain of equal to or more than 1 and equal to or less than 3 carbon atoms which may have a substituent; and when n−p is 2 or more, a plurality of R2s each independently represent an alkyl group having a straight chain or a branched chain of equal to or more than 1 and equal to or less than 3 carbon atoms which may have a substituent or a plurality of R2s may be bonded to each other to form a ring containing M in which the alkyl chain forming the ring has equal to or more than 1 and equal to or less than 3 carbon atoms and a portion constituting the ring does not contain a sulfur atom).