Spin caloritronics is the fusion research field based on the combination of spintronics, thermoelectrics, and thermal energy engineering, where the interplay between spin, charge, and heat currents has been extensively investigated. Recently, we have clarified detailed behaviors of various magneto-thermoelectric and thermo-spin effects and demonstrated novel thermal control functionalities realized by spin caloritronics by means of the active heat detection techniques called the lock-in thermography and lock-in thermoreflectance methods. In this article, we explain the measurement principles and features of these lock-in heat detection techniques, and review recent developments in spin caloritronics. These techniques are useful not only for elucidating physics of spin caloritronics but also for finding good magneto-thermoelectric and thermo-spin conversion materials. Keywords: Spin caloritronics, Magneto-thermoelectric effect,