An engine balancer device is provided that can prevent an increase in the number of component parts and the enlargement of an engine.The balancer weight includes a primary balancer 201 rotated at the same speed as, and in a counter direction to a crankshaft 105 and a coupling balancer for suppressing moment force resulting from the reciprocative weight of the engine 17. The coupling balancer is integrally provided on a driven gear 177 for transmitting rotation of the crankshaft 105 to the primary balancer 201.