the invention relates to a scheme for correctly reading data pits with a reader even if an optical recording card is fed slantwise . if the optical recording card is slanted relative to a line sensor for reading the card , the line sensor may ride on two or more data pit columns . however , discriminator pits are formed at the start and end of each data pit column so that the data can be processed after deciding if the optical recording card is disposed slantwise or not . a relatively short data pit column with discriminator pits formed at the start and end thereof is used . a plurality of data pit columns are disposed with a guide bar interposed therebetween . a readout signal from the discriminator pits is used for deciding if the data pit column has been read correctly , whereas a strobe signal read from the guide bar is used for initiating a memory selector .