A variable valve apparatus for an OHC type internal combustion engine which includes a crankcase, a cylinder block and a cylinder head placed in order on the crankcase and fastened together by a plurality of stud bolts extending through the cylinder block and the cylinder head in a cylinder axial line direction, a plurality of rocker arms (57, 58) arrayed and supported for rocking motion in a mutually neighboring relationship on a rocker arm shaft in the inside of the cylinder head and operable in an interlocking relationship with engine valves (61, 62), and a head cover placed on the cylinder head to cover the cylinder head, the variable valve apparatus comprising: a connection pin fitted for movement in an axial direction of the rocker arm shaft in the rocker arms (57, 58) positioned adjacent each other and movable between a connection position at which the connection pin connects the rocker arms (57, 58) positioned adjacent each other to each other for integral rocking motion and a disconnection position at which the connection pin disconnects the rocker arms (57, 58) from each other to allow independent rocking motion of each of the rocker arms (57, 58); and a pressing force transmission member (74, 76) configured to transmit pressing force of a pressing force generation source disposed outside the cylinder head to the connection pin to move the connection pin; the pressing force generation source being attached to a wall face of the cylinder head on which an ignition plug is provided in a projecting manner; an accommodation case (77, 78) which accommodates a main body of the pressing force generation source therein being provided at a position at which the accommodation case (77, 78) does not overlap with an ignition plug center axial line (Cs), which is directed by the ignition plug, as viewed in the cylinder axial line direction characterized in that the pressing force generation source has a plurality of attachment arm portions (77pr, 77qr, 77rr) formed around the accommodation case (77, 78) so as to extend radially along the wall face of the cylinder head, and the attachment arm portions (77pr, 77qr, 77rr) are attached only to the cylinder head, and wherein, from among the attachment arm portions (77pr, 77qr, 77rr), the attachment arm portion which extends in a direction overlapping with the ignition plug center axial line (Cs) as viewed in the cylinder axial line direction has a recessed portion formed thereon so as to be open toward the ignition plug side in such a manner that the recessed portion crosses but keeps away from the ignition plug center axial line (Cs). a connection pin fitted for movement in an axial direction of the rocker arm shaft in the rocker arms (57, 58) positioned adjacent each other and movable between a connection position at which the connection pin connects the rocker arms (57, 58) positioned adjacent each other to each other for integral rocking motion and a disconnection position at which the connection pin disconnects the rocker arms (57, 58) from each other to allow independent rocking motion of each of the rocker arms (57, 58); and a pressing force transmission member (74, 76) configured to transmit pressing force of a pressing force generation source disposed outside the cylinder head to the connection pin to move the connection pin; the pressing force generation source being attached to a wall face of the cylinder head on which an ignition plug is provided in a projecting manner; an accommodation case (77, 78) which accommodates a main body of the pressing force generation source therein being provided at a position at which the accommodation case (77, 78) does not overlap with an ignition plug center axial line (Cs), which is directed by the ignition plug, as viewed in the cylinder axial line direction