A main substrate which is arranged in one end section of a main apparatus body in the width direction is horizontally arranged using a free space in one end section of the mechanical component arrangement area in a main apparatus body in the width direction. A plurality of relay substrates are vertically provided in the upper-side position of the main substrate in the mechanical component arrangement area, and the main substrate is connected to the plurality of relay substrates through FFCs connected to respective connectors. A plurality of connectors are provided on the two relay substrates in order to connect to wirings from a printer mechanism section.