MILK BOTTLE

PROBLEM TO BE SOLVED: To provide a milk bottle ready for any sealing means of paper plug or a resin cap by forming a middle stage to fit the paper plug in an inner circumferential surface of a bottle mouth part, and forming a recessed step to engage a projection for engagement provided on an inner circumferential surface of a resin cap with an outer circumferential surface of the bottle mouth part. SOLUTION: A middle stage 3 to fit a paper plug to an inner circumferential surface of a bottle mouth part of a milk bottle is formed, and a recessed step 4 to engage a projection for engagement provided on an inner circumferential surface of a resin cap with an outer circumferential surface of the bottle mouth part 2. The middle stage 3 is formed to satisfy the condition that the distance L1 downward of a mouth top is about 4.5 mm, the stage width L2 is about 2 mm. The recessed step 4 is set to satisfy the condition that the distance L3 downward of the mouth top is about 7 mm, the stage width L4 is about 1.5 mm. A base part of the recessed step 4 is formed so as to be continuous to a bottle body 1 through a connection part 5 which is gradually curved and whose outside diameter is reduced. In addition, the angle to the horizontal plane of the recessed step 4 is preferably in the range of 4 deg. to 12 deg..