A muscle electrostimulation device has a main body having a contact surface fitted around an abdomen. The contact surface extends in an X direction encircling the abdomen and in a Y direction perpendicular to the X direction. The main body includes: a front part having a front electrode unit adapted to cause an electric current in the X direction in an abdominal rectus muscle and a pair of extensions extending from respective sides of the front part in the X direction and having side electrode units adapted to cause an electric current in the X direction to flow in an oblique abdominal muscle. Front recesses that recede in the Y direction are provided at positions in side portions of the front part along the Y direction that bisect the front part in the X direction.
