Liquid detection device, liquid container using the same, and method of producing liquid detection device

A liquid detection device comprising:

• a casing main body, a passage being formed in the casing main body and exposed in an opening;
• a sensor base that faces the passage in the opening formed in the casing main body;
• a sensor chip that includes a piezoelectric element, the sensor chip being provided on the sensor base on a side that is opposite to a side that faces the passage;
• a film that holds the sensor base in the opening and seals the opening;
• and
• a partition wall that divides the passage into an upstream side and an downstream side inside the casing main body,
• the sensor chip having a sensor cavity that receives a liquid that is a detection target;
• the sensor base having a first hole that guides the liquid from the upstream side of the passage to the sensor cavity, and a second hole that guides the liquid from the sensor cavity to the downstream side of the passage;
• and
• the sensor base being configured to come into contact with the casing main body through only the partition wall at a position between the first hole and the second hole in a depth direction of the opening.