A cleaning device adapted for microwave oven, comprising: a body part that is provided with an inner chamber for accommodating a cleaning liquid and a first opening communicating with the inner chamber; a head cap that surrounds the body part along a length direction of the body part and covers the first opening of the body part; a portion of the head cap, which portion corresponds to the first opening of the body part, is provided with multiple through holes, wherein the first opening and the multiple through holes form a gas passage for venting steam of the cleaning liquid within the inner chamber; and an intermediate part surrounding the body part, wherein the intermediate part is located between the body part and the head cap in the length direction of the body part; wherein the body part comprises an upper portion arranged with a locking groove, and the head cap comprises a first annular wall that surrounds the upper portion by extending downwards from an internal top surface of the head cap; the first annular wall is arranged with a second protrusion, wherein the second protrusion is clamped within the locking groove so as to connect the head cap with the body part together; the locking groove comprises a receiving part, a guiding part and a locking part, and the receiving part and the locking part communicate with each other through the guiding part; a ridged structure is disposed within the locking part substantially perpendicularly to an extending direction of the locking part; the second protrusion is a protruding block with a recess; when the second protrusion is clamped within the locking groove, the second protrusion slides into the locking part through the guiding part with the recess and the ridged structure to be engaged with each other. a body part that is provided with an inner chamber for accommodating a cleaning liquid and a first opening communicating with the inner chamber; a head cap that surrounds the body part along a length direction of the body part and covers the first opening of the body part; a portion of the head cap, which portion corresponds to the first opening of the body part, is provided with multiple through holes, wherein the first opening and the multiple through holes form a gas passage for venting steam of the cleaning liquid within the inner chamber; and an intermediate part surrounding the body part, wherein the intermediate part is located between the body part and the head cap in the length direction of the body part; wherein the body part comprises an upper portion arranged with a locking groove, and the head cap comprises a first annular wall that surrounds the upper portion by extending downwards from an internal top surface of the head cap; the first annular wall is arranged with a second protrusion, wherein the second protrusion is clamped within the locking groove so as to connect the head cap with the body part together; the locking groove comprises a receiving part, a guiding part and a locking part, and the receiving part and the locking part communicate with each other through the guiding part; a ridged structure is disposed within the locking part substantially perpendicularly to an extending direction of the locking part; the second protrusion is a protruding block with a recess; when the second protrusion is clamped within the locking groove, the second protrusion slides into the locking part through the guiding part with the recess and the ridged structure to be engaged with each other.