An electromagnetic wave sensor that limits the influence on bolometer membranes that is caused by heat from a local heat source is provided. Electromagnetic wave sensor has first substrate, second substrate that faces first substrate so as to form inner space between first substrate and second substrate, wherein second substrate transmits infrared rays; a plurality of bolometer membranes that is provided in inner space and that is supported by second substrate; local heat source that is formed in first substrate; first electric connection member that connects first substrate to second substrate; and lead that extends on or in second substrate and that connects first electric connection member to bolometer membrane.