We have studied the skeleton conformation of optically active polysilane homopolymer, poly(methyl((S)-2-methylbutyl)silane) (1), as a model of flexible chainlike polymers in solution, by means of various optical spectra (UV absorption, circular dichroism, fluorescence, fluorescence excitation, and fluorescence anisotropy), NMR spectra (C-13 and Si-29), intrinsic viscosity as a function of molecular weight of polymer, screw-sense-selective photolysis, and GPC analysis equipped with a photodiode array UV detector. From a comparison among its circular dichroism, UV absorption, fluorescence, and fluorescence excitation spectra, we concluded that both P-screw-sense, tight helical and M-screw-sense, loose helical segments coexist in the same chain of 1-diastereomeric helical segment-like block structure. The screw-sense-selective photolysis suggests that segments responsible for P- and M-screw-senses consist of nine silicon atoms. On the basis of this conformational model, modified 1* with almost a single P-screw-sense was reconstructed by the screw-sense-selective "cut-and-paste" procedure used for original 1.