A thick 25 ${mu}m$ thickness poled P(VDF/TrFE) film pyroelectric infrared ray sensor has been fabricated and then thin 1.6 ${mu}m$ thickness P(VDF/TrFE) film pyroelectric infrared ray sensor has been fabricated also. These thick and thin P(VDF/TrFE) film pyroelectric infrared ray sensor was mounted in TO-5 housing to detect infrared light of 5.5 ~ 14 ${mu}m$ wavelength for human body detecting with each other. The noise output voltage of the thick P(VDF/TrFE) film pyroelectric infrared ray sensor were 380 mV and NEP(noise equivalent power) is $3.95{ imes}10^{-7}$ W which is the similar value with the commercial pyroelectric infrared ray sensor using ceramic materials as a sensing material. The NEP and specific detectivity $D^*$ of the thin P(VDF/TrFE) film pyroelectric infrared ray sensor were $2.13{ imes}10^{-8}$ W and $9.37{ imes}106$ cm/W under emission energy of 13 ${mu}W/cm^2$ respectively. These result caused by lower thermal diffusion coefficient of a thin 1.6 ${mu}m$ thickness PVDF/TrFE film than the thick 25 ${mu}m$ thickness poled P(VDF/TrFE) film pyroelectric infrared ray sensor.