A push switch and mounting substrate arrangement comprising a mounting substrate and a push switch, said push switch comprising: a switch substrate (2, 7) having an L-shaped cross section, wherein said substrate has a front surface located perpendicular to a mounting surface of a mounting substrate at a side edge of the mounting substrate which does not have a cutout thereof, a back surface for mounting on the mounting substrate, and a side face; an accommodating recess provided on said front surface; a center contact provided so as to be substantially centralized in said accommodating recess; a pair of peripheral contacts each provided at a circumferential edge of said accommodating recess; a movable contact spring constructed so as to extend across said pair of peripheral contacts and designed to be brought into contact with said center contact when pressed; a protrusion provided on a front surface of said movable contact spring; and a connection pad (15A, 15B, 19) provided on said back surface and electrically connected to the mounting substrate, wherein a part of said back surface is located at the side edge of the mounting substrate, a portion of the mounting substrate is located in prolongation of said protrusion when viewed in a pressing direction of the protrusion, and a corner portion which is provided at the inside of said L-shaped cross section of said switch substrate is located at the side edge of the mounting substrate so that the force applied to press said protrusion is received by the mounting substrate, wherein said switch substrate is located so that a lower end of said switch substrate at said front surface side is flush with a lower end of the mounting substrate, wherein said switch substrate includes a first substrate which is bonded to said side edge of said mounting substrate and has said back surface, and a second substrate which is connected perpendicular to said first substrate so as to provide said L-shaped cross-section and to provide connection of the peripheral contacts on the first substrate to connection patterns (14A, 14B) on the second substrate, and has said connection pad,and wherein said center contact and said pair of peripheral contacts are provided on said first substrate, and said center contact, said pair of peripheral contacts, and said connection pad are electrically connected to each other by connecting said first substrate with said second substrate. a switch substrate (2, 7) having an L-shaped cross section, wherein said substrate has a front surface located perpendicular to a mounting surface of a mounting substrate at a side edge of the mounting substrate which does not have a cutout thereof, a back surface for mounting on the mounting substrate, and a side face; an accommodating recess provided on said front surface; a center contact provided so as to be substantially centralized in said accommodating recess; a pair of peripheral contacts each provided at a circumferential edge of said accommodating recess; a movable contact spring constructed so as to extend across said pair of peripheral contacts and designed to be brought into contact with said center contact when pressed; a protrusion provided on a front surface of said movable contact spring; and a connection pad (15A, 15B, 19) provided on said back surface and electrically connected to the mounting substrate, wherein a part of said back surface is located at the side edge of the mounting substrate, a portion of the mounting substrate is located in prolongation of said protrusion when viewed in a pressing direction of the protrusion, and a corner portion which is provided at the inside of said L-shaped cross section of said switch substrate is located at the side edge of the mounting substrate so that the force applied to press said protrusion is received by the mounting substrate, wherein said switch substrate is located so that a lower end of said switch substrate at said front surface side is flush with a lower end of the mounting substrate, wherein said switch substrate includes a first substrate which is bonded to said side edge of said mounting substrate and has said back surface, and a second substrate which is connected perpendicular to said first substrate so as to provide said L-shaped cross-section and to provide connection of the peripheral contacts on the first substrate to connection patterns (14A, 14B) on the second substrate, and has said connection pad,and wherein said center contact and said pair of peripheral contacts are provided on said first substrate, and said center contact, said pair of peripheral contacts, and said connection pad are electrically connected to each other by connecting said first substrate with said second substrate.