A pulse photometer comprising: a first variation acquirer which is configured to acquire a first variation corresponding to a light attenuation variation of a first light beam due to pulsation of blood in a subject, based on a first intensity signal corresponding to an intensity of the first light beam that is transmitted through or reflected from a body of the subject, and that has a first wavelength; a second variation acquirer which is configured to acquire a second variation corresponding to a light attenuation variation of a second light beam due to the pulsation, based on a second intensity signal corresponding to an intensity of the second light beam that is transmitted through or reflected from the body of the subject, and that has a second wavelength; a third variation acquirer which is configured to acquire a third variation corresponding to a light attenuation variation of a third light beam due to the pulsation, based on a third intensity signal corresponding to an intensity of the third light beam that is transmitted through or reflected from the body of the subject, and that has a third wavelength; and a concentration calculator which is configured to calculate a blood light absorber concentration in the blood, based on the first variation and the second variation; characterized by an estimated value calculator which is configured to calculate an estimated value of the third variation, based on the first variation and the second variation; and an evaluator which is configured to evaluate reliability of a calculated value of the blood light absorber concentration, based on the third variation acquired by the third variation acquirer, and the estimated value calculated by the estimated value calculator. a first variation acquirer which is configured to acquire a first variation corresponding to a light attenuation variation of a first light beam due to pulsation of blood in a subject, based on a first intensity signal corresponding to an intensity of the first light beam that is transmitted through or reflected from a body of the subject, and that has a first wavelength; a second variation acquirer which is configured to acquire a second variation corresponding to a light attenuation variation of a second light beam due to the pulsation, based on a second intensity signal corresponding to an intensity of the second light beam that is transmitted through or reflected from the body of the subject, and that has a second wavelength; a third variation acquirer which is configured to acquire a third variation corresponding to a light attenuation variation of a third light beam due to the pulsation, based on a third intensity signal corresponding to an intensity of the third light beam that is transmitted through or reflected from the body of the subject, and that has a third wavelength; and a concentration calculator which is configured to calculate a blood light absorber concentration in the blood, based on the first variation and the second variation; characterized by an estimated value calculator which is configured to calculate an estimated value of the third variation, based on the first variation and the second variation; and an evaluator which is configured to evaluate reliability of a calculated value of the blood light absorber concentration, based on the third variation acquired by the third variation acquirer, and the estimated value calculated by the estimated value calculator. <EOS>