A pickup apparatus of an optical card has an improved data transfer efficiency and miniaturization and thin shape of the apparatus can be realized. The length of a line segment connecting a center of an objective lens provided in a rotational optical unit and a center of a rotary drum is set to a length specified by a length in the major side direction on a recording surface of the optical card and (1+cos.theta./2). An optical pickup apparatus has: a fixed optical unit SOP; a rotary drum in reflecting mirrors for guiding a light beam B emitted from the fixed optical unit SOP to a recording surface of an optical card and an objective lens are mounted; and a rotational optical unit ROP having a rotary motor for rotating the rotary drum, wherein information is recorded and reproduced to and from the recording surface of the optical card. A length of a line segment connecting the center of the objective lens and the center of rotation of the rotary drum is decided on the basis of a length in the major side direction on the recording surface of the optical card and (1+cos.theta./2).