The invention provides an aliphatic polymer having a ketone group and ether bonding in its main chain, characterized by comprising structural units represented by the Formula (1) and by the Formula (2). ##STR00001## In the Formulae (1) and (2), Ra and Rb each independently represents a substituted or unsubstituted divalent aliphatic hydrocarbon group. Rc represents a substituted or unsubstituted divalent aliphatic hydrocarbon group having ether bonding in a terminal thereof, or a single bond. N1 represents an integer of 1 or more. N2 represents an integer of 0 or more. And, n1+n2 is in a range of 2 to 1000. The polymer preferably contains ether bonds and ketone groups in a ratio of 0.01 to 100. The polymer can be substantially comprised of a structural unit represented by the Formula (1) as a repeating unit. A resin composition containing as a component structural units represented by the Formula (1) is also provided. The resin composition may further comprise an electrically conductive powder.