A door latch device that is disposed on a door of a vehicle, and is configured to latch and unlatch a striker disposed on a main body side of the vehicle to close and open the door, the door latch device comprising: electric components including a motor; a machine mechanism configured to be driven by the motor; a circuit board electrically connected to the electric components; a case; a first cover forming a first housing space in which the motor and the machine mechanism are housed by covering one surface of the case; a second cover forming a second housing space in which the circuit board is housed by covering another surface of the case; and an external waterproof seal that is disposed between the case and the second cover, and waterproofs the second housing space against outside, wherein the case includes: a recessed part forming a part of the second housing space; a surrounding wall surrounding the recessed part; and a seal groove formed along an outer circumference of the surrounding wall and in which the external waterproof seal is disposed, the second housing space is formed by covering the recessed part by the second cover, and an entire circumference between the recessed part and the second cover is waterproofed by the external waterproof seal, the door latch device further comprising: a pin hole that is disposed in the case to establish communication between the first housing space and the second housing space; a pin that is erected from the circuit board to project to the first housing space through the pin hole, characterized in that it further comprises: a pin holder supporting the pin with respect to the circuit board by covering a periphery of a base of the pin; and an internal waterproof seal that is disposed between the pin holder and the pin hole, and waterproofs a space between the first housing space and the second housing space. electric components including a motor; a machine mechanism configured to be driven by the motor; a circuit board electrically connected to the electric components; a case; a first cover forming a first housing space in which the motor and the machine mechanism are housed by covering one surface of the case; a second cover forming a second housing space in which the circuit board is housed by covering another surface of the case; and an external waterproof seal that is disposed between the case and the second cover, and waterproofs the second housing space against outside, wherein the case includes: a recessed part forming a part of the second housing space; a surrounding wall surrounding the recessed part; and a seal groove formed along an outer circumference of the surrounding wall and in which the external waterproof seal is disposed, a recessed part forming a part of the second housing space; a surrounding wall surrounding the recessed part; and a seal groove formed along an outer circumference of the surrounding wall and in which the external waterproof seal is disposed, the second housing space is formed by covering the recessed part by the second cover, and an entire circumference between the recessed part and the second cover is waterproofed by the external waterproof seal, the door latch device further comprising: a pin hole that is disposed in the case to establish communication between the first housing space and the second housing space; a pin that is erected from the circuit board to project to the first housing space through the pin hole, characterized in that it further comprises: a pin holder supporting the pin with respect to the circuit board by covering a periphery of a base of the pin; and an internal waterproof seal that is disposed between the pin holder and the pin hole, and waterproofs a space between the first housing space and the second housing space. a pin hole that is disposed in the case to establish communication between the first housing space and the second housing space; a pin that is erected from the circuit board to project to the first housing space through the pin hole, characterized in that it further comprises: a pin holder supporting the pin with respect to the circuit board by covering a periphery of a base of the pin; and an internal waterproof seal that is disposed between the pin holder and the pin hole, and waterproofs a space between the first housing space and the second housing space. a pin holder supporting the pin with respect to the circuit board by covering a periphery of a base of the pin; and an internal waterproof seal that is disposed between the pin holder and the pin hole, and waterproofs a space between the first housing space and the second housing space.