An apparatus for detecting an azimuthal angle of a heat source, comprising: a controlling device, comprising: a circuit board; a micro-controller electrically connected to the circuit board; and a driving module electrically connected to the circuit board, wherein the driving module is electrically connected to the micro-controller via the circuit board; and a detecting device, comprising: a turntable connected to the driving module; a reference member disposed on the turntable; a positioning member installed on the turntable and having a target positioning portion, wherein the driving module is configured to drive the positioning member to rotate along an axis; an infrared sensor electrically connected to the circuit board for receiving an infrared signal transmitted into the detecting device through the positioning member, wherein a signal strength defined by an infrared signal transmitted into the infrared sensor through the target positioning portion of the positioning member is different from a signal strength defined by an infrared signal transmitted into the infrared sensor through the other portion of the positioning member; and an aligning member electrically connected to the controlling device, wherein the aligning member and the reference member co-define a starting time reference when the target positioning portion starts to rotate; characterized in that: the positioning member further has a plurality of condensing portions arranged around the target positioning portion, the target positioning portion has a plurality of convex lens arranged side by side, and each condensing portion is a convex lens, the size of each condensing portion is smaller than the size of each convex lens of the target positioning portion, the condensing portions are assembled to be a plurality of stacked C-shaped constructions, and the ends of the C-shaped constructions are connected to two opposite edges of the target positioning portion, and the number of convex lens of each C-shaped construction is greater than the number of convex lens of the target positioning portion. a controlling device, comprising: a circuit board; a micro-controller electrically connected to the circuit board; and a driving module electrically connected to the circuit board, a circuit board; a micro-controller electrically connected to the circuit board; and a driving module electrically connected to the circuit board, wherein the driving module is electrically connected to the micro-controller via the circuit board; and a detecting device, comprising: a turntable connected to the driving module; a reference member disposed on the turntable; a positioning member installed on the turntable and having a target positioning portion, wherein the driving module is configured to drive the positioning member to rotate along an axis; an infrared sensor electrically connected to the circuit board for receiving an infrared signal transmitted into the detecting device through the positioning member, wherein a signal strength defined by an infrared signal transmitted into the infrared sensor through the target positioning portion of the positioning member is different from a signal strength defined by an infrared signal transmitted into the infrared sensor through the other portion of the positioning member; and an aligning member electrically connected to the controlling device, wherein the aligning member and the reference member co-define a starting time reference when the target positioning portion starts to rotate; a turntable connected to the driving module; a reference member disposed on the turntable; a positioning member installed on the turntable and having a target positioning portion, wherein the driving module is configured to drive the positioning member to rotate along an axis; an infrared sensor electrically connected to the circuit board for receiving an infrared signal transmitted into the detecting device through the positioning member, wherein a signal strength defined by an infrared signal transmitted into the infrared sensor through the target positioning portion of the positioning member is different from a signal strength defined by an infrared signal transmitted into the infrared sensor through the other portion of the positioning member; and an aligning member electrically connected to the controlling device, wherein the aligning member and the reference member co-define a starting time reference when the target positioning portion starts to rotate; characterized in that: the positioning member further has a plurality of condensing portions arranged around the target positioning portion, the target positioning portion has a plurality of convex lens arranged side by side, and each condensing portion is a convex lens, the size of each condensing portion is smaller than the size of each convex lens of the target positioning portion, the condensing portions are assembled to be a plurality of stacked C-shaped constructions, and the ends of the C-shaped constructions are connected to two opposite edges of the target positioning portion, and the number of convex lens of each C-shaped construction is greater than the number of convex lens of the target positioning portion.