An instrument device comprising: a display panel arranged on the front side of an indicating instrument; a circuit board formed of a hard material on which the indicating instrument is mounted; a middle case arranged on the front side of the circuit board and formed of a resin material for placing the display panel; an upper case arranged on the front side of the middle case and formed of a resin material which allows seeing therethrough at least on a front surface thereof, a lower case formed of a resin material which covers the middle case and the circuit board, wherein the middle case is provided with a flange portion on a peripheral edge portion thereof for being held by being clamped between the upper and lower cases (50, 60), one of the upper case or the lower case is provided with locking portions on respective outer peripheral portions thereof at intervals, and the other one of the upper case or the lower case is provided with engaging portions configured to engage the locking portions corresponding to the engaging portions, characterized in that the middle case is integrally provided with a second locking portion configured to engage an inside of the lower case so as to clamp and hold the circuit board between the lower case and the middle case; the second locking portion is visible from an outside of the lower case, the lower case is provided with a rising wall portion formed so as to rise toward a circuit board side, and a placing portion continuing from the rising wall portion and supporting a back side of the circuit board, the placing portion is provided with an opening window portion, the circuit board is provided with a through hole at a position corresponding to the opening window portion, and the middle case is integrally provided with the second locking portion configured to engage a lower case side corresponding to the through hole and the opening window portion, the lower case being provided with a depressed space portion formed of the rising wall portion and the placing portion; and wherein the second locking portion is visible from the depressed space portion. a display panel arranged on the front side of an indicating instrument; a circuit board formed of a hard material on which the indicating instrument is mounted; a middle case arranged on the front side of the circuit board and formed of a resin material for placing the display panel; an upper case arranged on the front side of the middle case and formed of a resin material which allows seeing therethrough at least on a front surface thereof, a lower case formed of a resin material which covers the middle case and the circuit board, wherein the middle case is provided with a flange portion on a peripheral edge portion thereof for being held by being clamped between the upper and lower cases (50, 60), one of the upper case or the lower case is provided with locking portions on respective outer peripheral portions thereof at intervals, and the other one of the upper case or the lower case is provided with engaging portions configured to engage the locking portions corresponding to the engaging portions, characterized in that the middle case is integrally provided with a second locking portion configured to engage an inside of the lower case so as to clamp and hold the circuit board between the lower case and the middle case; the second locking portion is visible from an outside of the lower case, the lower case is provided with a rising wall portion formed so as to rise toward a circuit board side, and a placing portion continuing from the rising wall portion and supporting a back side of the circuit board, the placing portion is provided with an opening window portion, the circuit board is provided with a through hole at a position corresponding to the opening window portion, and the middle case is integrally provided with the second locking portion configured to engage a lower case side corresponding to the through hole and the opening window portion, the lower case being provided with a depressed space portion formed of the rising wall portion and the placing portion; and wherein the second locking portion is visible from the depressed space portion.