A coiled spring assembly comprising: a coiled spring having an end turn (9, 11) at each end of a body portion and a seat for the coiled spring attached to the end turn, wherein the coiled spring, the end turn (9, 11) of which is formed up to a first turn with a reduced diameter relative to the body portion, has between the end turn (9, 11) and the body portion a transition portion (13, 15) with a diameter gradually increasing from the end turn to the body portion, the seat for the coiled spring has a seat portion, a receiving surface of which is in contact with a bearing surface (9a, 11a) of the end turn (9, 11), a mounting shaft portion protruding from the receiving surface of the seat portion, an enlarged diameter portion formed at a front end of the mounting shaft portion for guiding press fit, the mounting shaft portion has an axial length defining a gap between the enlarged diameter portion of the seat for the coiled spring and the end turn (9, 11) in a free state in which the end turn is fitted to the mounting shaft portion and the bearing surface (9a, 11a) of the end turn (9, 11) is in contact with the receiving surface of the seat portion, and the transition portion (13, 15) circumvents the enlarged diameter portion while the bearing surface (9a, 11a) of the end turn (9, 11) is in contact with the receiving surface of the seat portion, characterized in that the transition portion (13, 15) is led axially outward from the seat before reaching the second turn, the first turn of the element wire located over the tip of the coiled spring having a clearance relative to the enlarged diameter portion in a free length state of the end turn (9, 11), the transition portion transitions not to come into contact with the enlarged diameter portion, and at a position of the further half turn on the transition portion, the transition portion is offset with the clearance on an outer peripheral side of the enlarged diameter portion and transitions to the body portion. a coiled spring having an end turn (9, 11) at each end of a body portion and a seat for the coiled spring attached to the end turn, wherein the coiled spring, the end turn (9, 11) of which is formed up to a first turn with a reduced diameter relative to the body portion, has between the end turn (9, 11) and the body portion a transition portion (13, 15) with a diameter gradually increasing from the end turn to the body portion, the seat for the coiled spring has a seat portion, a receiving surface of which is in contact with a bearing surface (9a, 11a) of the end turn (9, 11), a mounting shaft portion protruding from the receiving surface of the seat portion, an enlarged diameter portion formed at a front end of the mounting shaft portion for guiding press fit, the mounting shaft portion has an axial length defining a gap between the enlarged diameter portion of the seat for the coiled spring and the end turn (9, 11) in a free state in which the end turn is fitted to the mounting shaft portion and the bearing surface (9a, 11a) of the end turn (9, 11) is in contact with the receiving surface of the seat portion, and the transition portion (13, 15) circumvents the enlarged diameter portion while the bearing surface (9a, 11a) of the end turn (9, 11) is in contact with the receiving surface of the seat portion, characterized in that the transition portion (13, 15) is led axially outward from the seat before reaching the second turn, the first turn of the element wire located over the tip of the coiled spring having a clearance relative to the enlarged diameter portion in a free length state of the end turn (9, 11), the transition portion transitions not to come into contact with the enlarged diameter portion, and at a position of the further half turn on the transition portion, the transition portion is offset with the clearance on an outer peripheral side of the enlarged diameter portion and transitions to the body portion.