The present invention provides an improved metered dose inhaler utilizing the property of the aerosol canister. The metered dose inhaler includes: a housing body (2) an aerosol canister (3) including a canister body (3a), a valve stem (3b), and a spring urging the valve stem, wherein the valve stem (3b) is held at a fixed position inside the housing body (2), and wherein the canister body (3a) is supported inside the housing body (2) to be depressible against a spring force of the spring a dose counter (10) including display members (12) and (13) rotatably supported inside the housing body (2), and a control lever (14) swingably supported inside the housing body (2) to rotate the display member (13) and a control cap (20) including a junction member rotatably joined to the control lever (14), and a cap portion (20b) which sheaths the canister body (3a) from a bottom side of the canister body (3a), wherein the control cap (20) causes the control lever (14) to swing.本發明提供一種使用氣溶膠罐之性質之改良計量吸入器。此計量吸入器包括:殼體(2);氣溶膠罐(3),包含罐體(3a)、閥桿(3b)以及彈壓該閥桿之彈簧,其中閥桿(3b)被保持於殼體(2)內部之固定位置,且其中罐體(3a)被支承於殼體(2)內部,可抵抗彈簧之彈力而按壓;劑量計數器(10),包含被可旋轉地支承於殼體(2)內部之顯示構件(12)及(13)以及被可擺動地支承於殼體(2)內部以旋轉顯示構件(13)之控制桿(14);以及控制蓋(20),包含被可旋轉地連結於控制桿(14)之連結構件以及自罐體(3a)之底側覆蓋罐體(3a)之蓋部(20b),其中該控制蓋(20)使控制桿(14)擺動。1...計量吸入器2...殼體2f...薄膜部2g...通孔3...氣溶膠罐3a...罐體3b...閥桿4...吸嘴5...吸嘴蓋5a...突起10...劑量計數器11...支承構件12...顯示構件13...顯示構件14...控制桿20...控制蓋20b2...殼