This paper deals with an unknown input observer design which estimates a linear function of the dynamic and non-measured input vectors in the time domain for a bilinear model with the presence of an unknown input and constant time delays cited in state and control vectors. The observer gain is based on Lyapunov Krasovskii stability theory and results from a set of Linear Matrix Inequalities (LMI). The presented approach proposes the decomposition of the unknown inputs and provides an estimation of a functional state vector and a functional unknown input. Then, a numerical example is given to highlight the effectiveness of the proposed approach.