To provide a program downloading method capable of efficiently rewriting a program memory without increasing the storage capacity of a memory for work, an electronic device and a program regarding the program downloading method used in the electronic device performing control on the basis of the program stored on a rewritable program memory, the electronic device and the program.

For all of data for rewrite, the data for the rewrite are received, the data of a sector corresponding to the received data for the rewrite are read from the program memory to the memory for the work and editing corresponding to the data for the rewrite is performed on the memory for the work.