An object of the invention is to provide a novel dendritic polymer serving as an organic semiconductor material which is isotropic and which exhibits remarkably high carrier conductivity. Another object of the invention is to provide an electronic device employing the dendritic polymer. These objects are attained by a dendritic polymer having a branching structure including repeating units each having a branch portion, each of said repeating units having a structure represented by formula (1), and containing a linear portion X formed of an optionally substituted divalent organic group and a branch portion Y formed of an optionally substituted trivalent organic group: characterized in that the linear portion X contains at least one thienylene moiety and is at least partially conjugated with the branch portion Y, and in that the polymer reversibly assumes an insulative state and a metallic state, depending on the presence of an external factor.