Electric stringed musical instrument having stretchable frame body

A cello comprising

• a frame body including a stretchable frame changed between a shrunk position in proximity to a center line thereof and a stretched position spread from said center line,
• at least one string stretched over said frame body
• a sound generating system converting vibrations of said at least one string to an electric sound,
• wherein said frame body further includes a trunk providing said center line so that said stretchable frame is in close proximity to said trunk in said shrunk position, said stretchable frame has a pair of arms rotatable supported by said trunk and pads respectively connected to leading end portions of the arms of said pair so as to be changed between said shrunk position and said stretched position depending upon an angle between said arms and said center line, in which said pads has respective outer surfaces shaped similar to corresponding surface portions of a body of an acoustic stringed musical instrument where a player holds, said pair of arms spaced from said outer surfaces of said pads at said stretched position by a distance equal to a distance between said corresponding surface portions sandwiched between knees of said player.