This article presents a new micro-device for analysis of a laser-induced cellular photothermal effect using a microfabricated platinum resistance temperature detector (platinum RTD). The thermometer was fabricated with platinum thin layer using a microelectromechanical system (MEMS) technique and the microchannel was made of polydimethylsiloxane (PDMS) using a standard soft-lithography. Platinum RTD has 2μm of the electrode width with the serpentine shaped platinum element and the electric resistance at 0° C is 247.88Ω. To measure erythrocyte-specific heat variations, 1 to 300mW power tunable diode pumped solid state (DPSS) laser module was used with 532nm wavelength. Temperature variations of blood cells after laser-irradiation were measured using the platinum RTD. For manipulating the cells, a microfluidic channel and hydrodynamic focusing were used.