Inhaler device of a powder substance contained in a capsule of the type having an operculum formed by two parts (2', 2") coupled together along a main capsule axis, comprising: - a main body (10; 10a; 10b) having a first body portion (12; 12a; 12b) and a second body portion (14; 14a; 14b), said first body portion and second body portion defining jointly at least a first capsule seat part (16; 16a, 16a'; 16b, 16b') adapted to retain a respective first capsule part and being hinged to each other so as to be rotatable about a rotation body axis (X') parallel to the main capsule axis between a closed main body position, wherein said first body portion and second body portion are adapted to retain said first capsule part in the first capsule seat part, and an open main body position adapted to allow the expulsion of the first capsule part from the first capsule seat part; - at least one slide (18; 18a; 18b), the inhaler device being characterized in that the at least one slide (18; 18a; 18b) is formed by a first slide portion (20; 20a; 20b) and a second slide portion (22; 22a; 22b), said first slide portion and second slide portion jointly defining a second capsule seat part (24; 24a, 24a'; 24b, 24b') adapted to retain a respective second capsule part (2") and being hinged to each other so as to be rotatable about a slide rotation axis (X") parallel to the main capsule axis between a closed slide position, wherein said first slide portion and second slide portion are adapted to retain said second capsule part in the second capsule seat part, and an open slide position adapted to allow the expulsion of the second capsule part from the second capsule seat part; wherein each slide portion is housed in a respective body portion and wherein each slide is translatable along a withdrawal axis parallel to said main capsule axis between an advanced position, in which the first and the second capsule seat part are placed in mutual contact so as to form a capsule seat for receiving a capsule, and a retracted position, in which the two capsule seat parts are spaced so as to cause separation of the two capsule parts. - a main body (10; 10a; 10b) having a first body portion (12; 12a; 12b) and a second body portion (14; 14a; 14b), said first body portion and second body portion defining jointly at least a first capsule seat part (16; 16a, 16a'; 16b, 16b') adapted to retain a respective first capsule part and being hinged to each other so as to be rotatable about a rotation body axis (X') parallel to the main capsule axis between a closed main body position, wherein said first body portion and second body portion are adapted to retain said first capsule part in the first capsule seat part, and an open main body position adapted to allow the expulsion of the first capsule part from the first capsule seat part; - at least one slide (18; 18a; 18b), the inhaler device being characterized in that the at least one slide (18; 18a; 18b) is formed by a first slide portion (20; 20a; 20b) and a second slide portion (22; 22a; 22b), said first slide portion and second slide portion jointly defining a second capsule seat part (24; 24a, 24a'; 24b, 24b') adapted to retain a respective second capsule part (2") and being hinged to each other so as to be rotatable about a slide rotation axis (X") parallel to the main capsule axis between a closed slide position, wherein said first slide portion and second slide portion are adapted to retain said second capsule part in the second capsule seat part, and an open slide position adapted to allow the expulsion of the second capsule part from the second capsule seat part; wherein each slide portion is housed in a respective body portion and wherein each slide is translatable along a withdrawal axis parallel to said main capsule axis between an advanced position, in which the first and the second capsule seat part are placed in mutual contact so as to form a capsule seat for receiving a capsule, and a retracted position, in which the two capsule seat parts are spaced so as to cause separation of the two capsule parts.