Balancer shaft for an internal combustion engine

Balancer shaft (20) with at least one balance weight portion (43,44,45) for an internal combustion engine, said balancer shaft is rotationally driven by a crankshaft (5) of said engine. The balancer shaft comprises a weight portion (20A) and a non-weight portion (20B), wherein a damper means (56) is interposed between said weight portion and said non-weight portion and/or said balancer shaft comprises at least two balance weight portions (44,45) which are constituting a balance weight, said balance weight portions are arranged on both sides of a bearing portion (20c) of said balancer shaft.