The present invention provides a polydialkylsilane, and a method for producing a polydialkylsilane, including a step of adding a compound represented by formula (I) (in formula (I), R1 and R2 independently represent an alkyl group, and X1 and X2 independently represent a halogen atom) to an organic solvent containing an alkali metal, in which 0.010 [hr−1]≦the average addition rate of compound (I) [moles·hr−1]/the amount of the alkali metal [moles]≦0.055 [hr−1].