A controller shifting device for interconnecting an armrest and a controller of a powered wheelchair, said controller shifting device characterized by: an adjustment mechanism including a first connection seat that is adapted to be secured to a bottom side of the armrest, a casing that has two opposite first and second end portions (322, 323) and that is connected pivotally to said first connection seat in an inclined manner relative to the armrest, and a second connection seat that is connected to said second end portion for installation of the controller, said first connection seat having a first shaft that extends upward relative to said casing from said first end portion, and a first mount body that is secured to and extends upwardly and obliquely relative to said casing from said first shaft for connection with the armrest, said casing being rotatable about said first shaft together with said second connection seat between an operating position where said second connection seat is situated in front of the armrest, and a folded position where said second connection seat is situated at one side of the armrest, one of said first and second end portions (322, 323) extends upward and forward relative to the armrest when said casing is in the operating position or in the folded position, wherein, when said casing rotates rearward from the operating position to the folded position, said second end portion revolves downward and rearward relative to the armrest to descend a top end of said second connection seat to a level lower than a top end of said first mount body, thereby placing the controller below the armrest. an adjustment mechanism including a first connection seat that is adapted to be secured to a bottom side of the armrest, a casing that has two opposite first and second end portions (322, 323) and that is connected pivotally to said first connection seat in an inclined manner relative to the armrest, and a second connection seat that is connected to said second end portion for installation of the controller, said first connection seat having a first shaft that extends upward relative to said casing from said first end portion, and a first mount body that is secured to and extends upwardly and obliquely relative to said casing from said first shaft for connection with the armrest, said casing being rotatable about said first shaft together with said second connection seat between an operating position where said second connection seat is situated in front of the armrest, and a folded position where said second connection seat is situated at one side of the armrest, one of said first and second end portions (322, 323) extends upward and forward relative to the armrest when said casing is in the operating position or in the folded position, wherein, when said casing rotates rearward from the operating position to the folded position, said second end portion revolves downward and rearward relative to the armrest to descend a top end of said second connection seat to a level lower than a top end of said first mount body, thereby placing the controller below the armrest. a first connection seat that is adapted to be secured to a bottom side of the armrest, a casing that has two opposite first and second end portions (322, 323) and that is connected pivotally to said first connection seat in an inclined manner relative to the armrest, and a second connection seat that is connected to said second end portion for installation of the controller, said first connection seat having a first shaft that extends upward relative to said casing from said first end portion, and a first mount body that is secured to and extends upwardly and obliquely relative to said casing from said first shaft for connection with the armrest, said casing being rotatable about said first shaft together with said second connection seat between an operating position where said second connection seat is situated in front of the armrest, and a folded position where said second connection seat is situated at one side of the armrest, one of said first and second end portions (322, 323) extends upward and forward relative to the armrest when said casing is in the operating position or in the folded position, wherein, when said casing rotates rearward from the operating position to the folded position, said second end portion revolves downward and rearward relative to the armrest to descend a top end of said second connection seat to a level lower than a top end of said first mount body, thereby placing the controller below the armrest.