An electrical power tool (1) includes a housing (10,20,30) , an electrical motor (21) , a motion conversion mechanism (36) , a counterweight holding member (73) , a counterweight (74) , and support members (71,72) . The electrical motor (21) is accommodated in the housing (10,20,30) . The motion conversion mechanism (36) is configured to convert a rotary motion of the electrical motor (21) into a reciprocation motion. The counterweight holding member (73) extends in a direction perpendicular to directions of the reciprocation motion and is capable of being elastically deformed in the directions of the reciprocation motion. The counterweight (74) is supported by the counterweight holding member (73) and is capable of reciprocating in the directions of reciprocation motion together with the counterweight holding member (73) . The support members (71,72) are positioned away from the counterweight (74) by a predetermined distance for supporting the counterweight holding member (73) to the housing (10,20,30) . The counterweight (74) is interposed between or among the support members (71,72) .