A physical quantity measuring device comprising: a cylindrical case comprising a circumferential portion with a through hole formed therein; a sensor module housed in the cylindrical case and configured to detect a physical quantity; a joint attached with the sensor module, the joint being disposed to cover a first opening of the cylindrical case; a cap member disposed to cover a second opening of the cylindrical case; a circuit board comprising an electronic circuit configured to receive a signal detected by the sensor module and an electronic adjuster configured to adjust the electronic circuit, the circuit board being housed in the cylindrical case; a sealing member (8, 8A) attached to the through hole; an adjuster member (9, 9A) configured to adjust the electronic adjuster; and a cover member (10, 10A) attached to the electronic adjuster to cover the electronic adjuster, wherein the electronic adjuster comprises an engaged portion disposed to face the through hole, the sealing member (8, 8A) is provided with a housing recess (83, 83A) opened to an outside of the cylindrical case and a communication hole (84, 84A) that brings the housing recess (83, 83A) into communication with an interior of the cylindrical case, the adjuster member (9, 9A) comprises a shaft (91, 91A) hermetically attached in the communication hole (84, 84A), an engagement portion (92, 92A) provided at a first end of the shaft (91, 91A) and configured to engage with the engaged portion, and an operable portion (93, 93A) provided at a second end of the shaft (91, 91A) and housed in the housing recess (83, 83A), the cover member (10, 10A) comprises a cover body (101, 101A) covering the electronic adjuster, and a guide (102, 102A) configured to guide the engagement portion (92, 92A) to a position corresponding to the engaged portion, a first groove is formed on the shaft (91, 91A) along an outer circumference of the shaft (91, 91A), the guide (102, 102A) is provided with a first projection engageable with the first groove, the shaft is provided with a projection projecting along the outer circumference and engageable with the first projection, and the cover member is an elastic component that is configured to bias the projection of the adjuster member with the first projection in a direction for separating the engagement portion from the engaged portion in an axial direction of the shaft. a cylindrical case comprising a circumferential portion with a through hole formed therein; a sensor module housed in the cylindrical case and configured to detect a physical quantity; a joint attached with the sensor module, the joint being disposed to cover a first opening of the cylindrical case; a cap member disposed to cover a second opening of the cylindrical case; a circuit board comprising an electronic circuit configured to receive a signal detected by the sensor module and an electronic adjuster configured to adjust the electronic circuit, the circuit board being housed in the cylindrical case; a sealing member (8, 8A) attached to the through hole; an adjuster member (9, 9A) configured to adjust the electronic adjuster; and a cover member (10, 10A) attached to the electronic adjuster to cover the electronic adjuster, wherein the electronic adjuster comprises an engaged portion disposed to face the through hole, the sealing member (8, 8A) is provided with a housing recess (83, 83A) opened to an outside of the cylindrical case and a communication hole (84, 84A) that brings the housing recess (83, 83A) into communication with an interior of the cylindrical case, the adjuster member (9, 9A) comprises a shaft (91, 91A) hermetically attached in the communication hole (84, 84A), an engagement portion (92, 92A) provided at a first end of the shaft (91, 91A) and configured to engage with the engaged portion, and an operable portion (93, 93A) provided at a second end of the shaft (91, 91A) and housed in the housing recess (83, 83A), the cover member (10, 10A) comprises a cover body (101, 101A) covering the electronic adjuster, and a guide (102, 102A) configured to guide the engagement portion (92, 92A) to a position corresponding to the engaged portion, a first groove is formed on the shaft (91, 91A) along an outer circumference of the shaft (91, 91A), the guide (102, 102A) is provided with a first projection engageable with the first groove, the shaft is provided with a projection projecting along the outer circumference and engageable with the first projection, and the cover member is an elastic component that is configured to bias the projection of the adjuster member with the first projection in a direction for separating the engagement portion from the engaged portion in an axial direction of the shaft.