[en] Research and development is being conducted aimed at a stable and highly reproducible system for the realization of a laser-plasma electron accelerator. This paper outlines the development of key technologies for electron acceleration using the multi-step acceleration scheme that was developed in the ImPACT program. It explains the development state of the following component technologies: (1) electron source using supersonic pulse gas jet, (2) electron beam optical system driven by a discharge pulse that selects the energy of generated electron bunches, and (3) plasma optical waveguide for accelerating beams for a long distance. It also introduces an electron beam transport line using pulsed quadrupole magnetic lens for light source application built on the laser acceleration platform. (A.O.)