An object of the invention is to provide an electronic component mounting device and a work method of the electronic component mounting device, capable of ensuring safety of an operator who accesses a work line through a door portion, and avoiding reduction of workability. A space defined by a base (11) and a cover member (14) is partitioned by a partition member (15) to define a plurality of work line storing spaces (SP1). A plurality of work lines (12) are stored in the respective work line storing spaces (SP1) individually. When any of a plurality of door portions (14a) provided in the cover member (14) so as to allow an access to an inside of the respective work line storing spaces (SP1) is opened, an operation of a work line (12) stored in a work line storing space (SP1) accessible through the opened door portion (14a) is stopped.