A powered working machine which drives a tip tool by power of a driving source, comprising: a tool supporting member to which the tip tool is fixed; a tool fixing member which cooperates with the tool supporting member to clamp and fix the tip tool in a direction along an axis line; a fixing mechanism which is arranged so as to be movable in the direction along the axis line and which generates a force with which the tool supporting member and the tool fixing member clamp the tip tool; an operating member which moves the fixing mechanism by an operator's operation and can generate or release the force; and an attachment mechanism which can attach/detach the tool fixing member to/from the tool supporting member, characterized in that the tool fixing member can move in a direction along the axis line, and has a fixed state in which the tip tool is fixed to the tool supporting member and a released state in which the tip tool is not fixed to the tool supporting member, and the attachment mechanism includes: a lock member which can move in a direction crossing the axis line, and which has a locked state in which a state of attachment of the tool fixing member to the tool supporting member is maintained and an unlocked state in which the tool fixing member can be detached from the tool supporting member; and a guide member which is rotated so as to center the axis line by an operator's operation, and which has a first rotation position at which the lock member is put in the locked state and a second rotation position at which the lock member is put in the unlocked state, the operating member and the guide member are separate members, wherein the tip tool can be detached from the tool supporting member by moving the fixing mechanism in the direction along the axis line, and then, rotating the guide member. a tool supporting member to which the tip tool is fixed; a tool fixing member which cooperates with the tool supporting member to clamp and fix the tip tool in a direction along an axis line; a fixing mechanism which is arranged so as to be movable in the direction along the axis line and which generates a force with which the tool supporting member and the tool fixing member clamp the tip tool; an operating member which moves the fixing mechanism by an operator's operation and can generate or release the force; and an attachment mechanism which can attach/detach the tool fixing member to/from the tool supporting member, characterized in that the tool fixing member can move in a direction along the axis line, and has a fixed state in which the tip tool is fixed to the tool supporting member and a released state in which the tip tool is not fixed to the tool supporting member, and the attachment mechanism includes: a lock member which can move in a direction crossing the axis line, and which has a locked state in which a state of attachment of the tool fixing member to the tool supporting member is maintained and an unlocked state in which the tool fixing member can be detached from the tool supporting member; and a guide member which is rotated so as to center the axis line by an operator's operation, and which has a first rotation position at which the lock member is put in the locked state and a second rotation position at which the lock member is put in the unlocked state, the operating member and the guide member are separate members, wherein the tip tool can be detached from the tool supporting member by moving the fixing mechanism in the direction along the axis line, and then, rotating the guide member. a lock member which can move in a direction crossing the axis line, and which has a locked state in which a state of attachment of the tool fixing member to the tool supporting member is maintained and an unlocked state in which the tool fixing member can be detached from the tool supporting member; and a guide member which is rotated so as to center the axis line by an operator's operation, and which has a first rotation position at which the lock member is put in the locked state and a second rotation position at which the lock member is put in the unlocked state, the operating member and the guide member are separate members, wherein the tip tool can be detached from the tool supporting member by moving the fixing mechanism in the direction along the axis line, and then, rotating the guide member.