Dependence of elastic modulus of micro cantilever fabricated by micro-stereolithography (μSL) on irradiation laser power is investigated in this study. The samples are formed by changing the irradiation laser power of μSL system and postcure processing time. A device for measuring deflection of the micro cantilever and applied load is developed. Then, the elastic moduli of the samples are evaluated from the gradient of the measured load-deflection relation and the formula of the strength of materials. Results show that the elastic modulus of the micro cantilever made by μSL is depend on the irradiation laser power. That is, the mechanical property of micro structures can be controlled by the irradiation laser power and post cure process.