Unit which has a connection terminal and an electronic device

An electronic device comprising:

• a substrate;
• an electronic component on the substrate;
• a casing comprising a first surface, a second surface which is opposite to the first surface and which faces the substrate, and an attachment hole which extends between the first surface and the second surface, the casing being attached to the substrate;
• and
• a connection terminal comprising a connection portion in the attachment hole from a side of the second surface and protruding from the first surface, a flange at a proximal end of the connection portion in an insertion direction and which has a size that prevents the flange passing through the attachment hole and which faces the second surface, and a holding portion which holds the casing between this holding portion and the flange to face the first surface.