A heater-integrated filter taking in a portion of a fluid of a rotating machine or an external fluid and generating a seal gas for performing sealing of the fluid in the rotating machine, the heater-integrated filter comprising: a casing where an intake port and a discharge port are formed, the intake port taking in the portion of the fluid from the rotating machine or the external fluid and the discharge port discharging the fluid or the external fluid; a filter body disposed in the casing, the fluid from the intake port or the external fluid passing through the filter body; and rod-like heaters which are disposed inside the casing and along which the fluid or the external fluid that has passed through the filter body is capable of flowing toward the discharge port along an extension direction along an outer peripheral surface, wherein the casing includes a body portion having a tubular shape about an axis and having a through-hole penetrating the body portion in the direction of the axis and a lid portion detachably covering the through-hole with respect to the body portion and supporting one end of the filter body, the heaters are disposed inside and outside the body portion such that the extension direction is along the axis, the heaters are provided so as to be spaced apart from each other in a circumferential direction of the casing, and the heaters are provided only in a region as a portion in the circumferential direction, the heater is provided with a tubular member spaced apart from the heater so as to cover the outer peripheral surface, and the fluid or the external fluid is capable of flowing through a gap between the heater and the tubular member, characterized in that the filter body has a tubular shape about the axis, a pair of wall portions spaced apart from each other in the direction of the axis are provided in the casing and the wall portions partition an inner portion of the casing into a first space, a second space, and a third space isolated from one another toward one side in the direction of the axis, the intake port is open to the third space, the discharge port is open to the second space, the filter body is disposed in the first space, an introduction path is connected to the filter body, the introduction path is open to the third space, and the fluid or the external fluid is capable of flowing through the introduction path, and the gap between the tubular member and the heater allows the first space and the second space to communicate with each other. a casing where an intake port and a discharge port are formed, the intake port taking in the portion of the fluid from the rotating machine or the external fluid and the discharge port discharging the fluid or the external fluid; a filter body disposed in the casing, the fluid from the intake port or the external fluid passing through the filter body; and rod-like heaters which are disposed inside the casing and along which the fluid or the external fluid that has passed through the filter body is capable of flowing toward the discharge port along an extension direction along an outer peripheral surface, wherein the casing includes a body portion having a tubular shape about an axis and having a through-hole penetrating the body portion in the direction of the axis and a lid portion detachably covering the through-hole with respect to the body portion and supporting one end of the filter body, the heaters are disposed inside and outside the body portion such that the extension direction is along the axis, the heaters are provided so as to be spaced apart from each other in a circumferential direction of the casing, and the heaters are provided only in a region as a portion in the circumferential direction, the heater is provided with a tubular member spaced apart from the heater so as to cover the outer peripheral surface, and the fluid or the external fluid is capable of flowing through a gap between the heater and the tubular member, the filter body has a tubular shape about the axis, a pair of wall portions spaced apart from each other in the direction of the axis are provided in the casing and the wall portions partition an inner portion of the casing into a first space, a second space, and a third space isolated from one another toward one side in the direction of the axis, the intake port is open to the third space, the discharge port is open to the second space, the filter body is disposed in the first space, an introduction path is connected to the filter body, the introduction path is open to the third space, and the fluid or the external fluid is capable of flowing through the introduction path, and the gap between the tubular member and the heater allows the first space and the second space to communicate with each other.