To provide an air purifier and a blade body for air purifying in which a weight of the whole blade body is kept roughly balanced, and the blade body is simply and easily replaced.

The blade body 8 of a blower part 3 composing the air purifier 1 is rotated and stopped based on a detection signal outputted from a fouling detection sensor 13. Clean air purified and filtered by an air purifying filter 11 and negative ion generated by tourmaline microparticles 12 are discharged in a desired direction to reduce amount of positive ion in surroundings and human body. A front surface cover 5 of the blower part 3 is removed from the back surface cover 4 and a whole body of the blade body 8 having the air purifying filter 11 is removed from a rotating shaft 6b of a motor 6a.