A coin discriminating apparatus includes a coin passage member for supporting a lower surface of a coin, a first transporting belt disposed above the coin passage member for holding the coin between the coin passage member and itself, thereby transporting it, a first light source for emitting light via a first transparent passage portion formed in the coin passage member toward the lower surface of the coin on the coin passage member, a first light detector for photoelectrically detecting light emitted from the first light source and reflected from the lower surface of the coin via the first transparent portion and producing pattern data of the lower surface of the coin, a second transporting belt for supporting the lower surface of the coin, a coin passage forming member disposed above the second transporting belt for holding the coin between the lower surface thereof and the second transporting belt, thereby transporting it, a second light source for emitting light via a second transparent passage portion formed in the coin passage forming member toward an upper surface of the coin being supported and transported by the second transporting belt, a second light detector for photoelectrically detecting light emitted from the second light source and reflected from the upper surface of the coin via the second transparent portion and producing pattern data of the upper surface of the coin, a first pattern data memory for storing the pattern data of the lower surface of the coin, a second pattern data memory for storing the pattern data of the upper surface of the coin, a reference pattern data memory for storing reference pattern data of coins of each denomination, a discriminator for comparing the pattern data of the lower surface of the coin with the reference pattern data of coins of each denomination and comparing the pattern data of the upper surface of the coin with the reference pattern data of coins of each denomination, thereby discriminating whether or not the coin is acceptable and the denomination of the coin. According to the thus constituted coin discriminating apparatus, it is possible to discriminate whether or not coins are acceptable and the denominations of coins with high accuracy even when the coins has a common pattern on one side surface thereof but a different pattern on the other side surface thereof like Euro coins.