Fireplace boiler, comprising: a main combustion chamber disposed at an outdoor side, having a first combustion chamber and a second combustion chamber separated by a stoker therein, and having a stove pipe connected to a top of the main combustion chamber at the outdoor side and an air adjuster coupled to a lower end of a rear outer side; an indoor port extending from and communicating with the main combustion chamber, positioned at an indoor side, and having a door at a front side thereof; a hot water circulation pipe having combustion pipes spaced from each other with regular intervals over the first combustion chamber with flame passages therebetween, a hot water outlet disposed around the combustion pipes and positioned at an upper portion of the main combustion chamber, and a hot water inlet disposed at a rear portion of the main combustion chamber; a damper disposed on a rotary shaft in the stove pipe of the main combustion chamber, supporting rods fixed to a side of the main combustion chamber, connection bars supported by the supporting rods, with a first end connected to a side of the damper, and a damper adjuster connected to the connection bars in order to move up and down the damper when the connection bars are pulled; an outdoor port disposed at a lower portion of the rear side of the main combustion chamber; the fireplace boiler being characterized in that it further comprises: a hot air circulation pipe having hot air outlets disposed through an upper portion of a front side of the indoor port and hot air inlets disposed through a lower portion of the front side of the indoor port, connecting the hot air outlets and the hot air inlets being connected, and being positioned through the first combustion chamber and the second combustion chamber; a cleaning socket disposed at an upper portion of a rear side of the main combustion chamber; and an air intake port for sucking exterior air disposed outside the main combustion chamber, an air intake line extending from the air intake port, an air exit port disposed in the indoor port to supply exterior air flowing inside through the air intake line to the first combustion chamber, and an ash shield covering the air exit port to block ashes. a main combustion chamber disposed at an outdoor side, having a first combustion chamber and a second combustion chamber separated by a stoker therein, and having a stove pipe connected to a top of the main combustion chamber at the outdoor side and an air adjuster coupled to a lower end of a rear outer side; an indoor port extending from and communicating with the main combustion chamber, positioned at an indoor side, and having a door at a front side thereof; a hot water circulation pipe having combustion pipes spaced from each other with regular intervals over the first combustion chamber with flame passages therebetween, a hot water outlet disposed around the combustion pipes and positioned at an upper portion of the main combustion chamber, and a hot water inlet disposed at a rear portion of the main combustion chamber; a damper disposed on a rotary shaft in the stove pipe of the main combustion chamber, supporting rods fixed to a side of the main combustion chamber, connection bars supported by the supporting rods, with a first end connected to a side of the damper, and a damper adjuster connected to the connection bars in order to move up and down the damper when the connection bars are pulled; a hot air circulation pipe having hot air outlets disposed through an upper portion of a front side of the indoor port and hot air inlets disposed through a lower portion of the front side of the indoor port, connecting the hot air outlets and the hot air inlets being connected, and being positioned through the first combustion chamber and the second combustion chamber; a cleaning socket disposed at an upper portion of a rear side of the main combustion chamber; and an air intake port for sucking exterior air disposed outside the main combustion chamber, an air intake line extending from the air intake port, an air exit port disposed in the indoor port to supply exterior air flowing inside through the air intake line to the first combustion chamber, and an ash shield covering the air exit port to block ashes.