A straight switching device comprises: a body portion, which is disposed with an inlet waterway and a mounting groove penetrating and in communication with the inlet waterway; wherein the device further comprises: a water dividing shaft sleeve, which is configured to be relatively secured in the mounting groove, an isolation portion is secured in the water dividing shaft sleeve to enable the water dividing shaft sleeve to define two water dividing passages (22, 23) oppositely isolated, and each water dividing passage (22, 23) is concave to define a water dividing hole (221, 231) penetrating an inner side and an outer side; and a switching housing, which is disposed in the mounting groove and surrounds an outer side of the water dividing shaft sleeve, and the switching housing is configured to rotate relative to the body portion and the water dividing shaft sleeve; the switching housing is disposed with one or more water inlets (311, 312) penetrating an inner side and an outer side, a water dividing cavity configured to be in communication with the water dividing holes (221, 231) is defined between the switching housing and the water dividing shaft sleeve, the inlet waterway is in communication with the water dividing cavity by the mounting groove and the one or more water inlets (311, 312); the switching housing is disposed with sealing portions (331, 332) configured to hermetically cooperate with the water dividing holes (221, 231), the switching housing rotates to control the sealing portions (331, 332) to seal the water dividing holes (221, 231) whether or not to at least enable the two water dividing passages (22, 23) to be switched to be in communication with the water dividing cavity. a body portion, which is disposed with an inlet waterway and a mounting groove penetrating and in communication with the inlet waterway; wherein the device further comprises: a water dividing shaft sleeve, which is configured to be relatively secured in the mounting groove, an isolation portion is secured in the water dividing shaft sleeve to enable the water dividing shaft sleeve to define two water dividing passages (22, 23) oppositely isolated, and each water dividing passage (22, 23) is concave to define a water dividing hole (221, 231) penetrating an inner side and an outer side; and a switching housing, which is disposed in the mounting groove and surrounds an outer side of the water dividing shaft sleeve, and the switching housing is configured to rotate relative to the body portion and the water dividing shaft sleeve; the switching housing is disposed with one or more water inlets (311, 312) penetrating an inner side and an outer side, a water dividing cavity configured to be in communication with the water dividing holes (221, 231) is defined between the switching housing and the water dividing shaft sleeve, the inlet waterway is in communication with the water dividing cavity by the mounting groove and the one or more water inlets (311, 312); the switching housing is disposed with sealing portions (331, 332) configured to hermetically cooperate with the water dividing holes (221, 231), the switching housing rotates to control the sealing portions (331, 332) to seal the water dividing holes (221, 231) whether or not to at least enable the two water dividing passages (22, 23) to be switched to be in communication with the water dividing cavity. a water dividing shaft sleeve, which is configured to be relatively secured in the mounting groove, an isolation portion is secured in the water dividing shaft sleeve to enable the water dividing shaft sleeve to define two water dividing passages (22, 23) oppositely isolated, and each water dividing passage (22, 23) is concave to define a water dividing hole (221, 231) penetrating an inner side and an outer side; and a switching housing, which is disposed in the mounting groove and surrounds an outer side of the water dividing shaft sleeve, and the switching housing is configured to rotate relative to the body portion and the water dividing shaft sleeve; the switching housing is disposed with one or more water inlets (311, 312) penetrating an inner side and an outer side, a water dividing cavity configured to be in communication with the water dividing holes (221, 231) is defined between the switching housing and the water dividing shaft sleeve, the inlet waterway is in communication with the water dividing cavity by the mounting groove and the one or more water inlets (311, 312); the switching housing is disposed with sealing portions (331, 332) configured to hermetically cooperate with the water dividing holes (221, 231), the switching housing rotates to control the sealing portions (331, 332) to seal the water dividing holes (221, 231) whether or not to at least enable the two water dividing passages (22, 23) to be switched to be in communication with the water dividing cavity.