Electronic component device, method of mounting electronic component device on circuit board, and mounting structure of electronic component device on circuit board

An electronic component device comprising:

• a mount substrate including an outer electrode on one principal surface and a mount electrode on another principal surface;
• at least one substrate component including a terminal electrode on one principal surface, and that is mounted on the mount substrate by the terminal electrode being joined to the mount electrode;
• and
• a sealing resin layer that is provided on the mount substrate on which the at least one substrate component is mounted;
• wherein
• the sealing resin layer includes an increased thickness region, and a top surface including an inclination;
• a plurality of the outer electrodes are provided;
• the outer electrodes include a signal outer electrode and a ground outer electrode;
• and
• when viewed in a planar direction:
• the mount substrate includes a region with an increased formation density of the ground outer electrode;
• and
• the increased thickness region of the sealing resin layer and the region of the mount substrate with the increased formation density of the ground outer electrode overlap each other.