A brain activity estimation device (10) is provided with: an image data acquiring means (20) and a brain activity estimating means (30). The image data acquiring means (20) acquires captured image data of a human face time sequentially. The brain activity estimating means (30) includes: an RGB processing unit (31) a blood circulation level calculating unit (33) and an estimating unit (35). The RGB processing unit (31) applies RGB processing to the captured image data acquired by the image data acquiring means (20) thus decomposing the captured image data into three color components namely an R component a G component and a B component. The blood circulation level calculating unit (33) calculates time sequentially blood circulation level data of the face on the basis of the RGB data of the captured image data obtained by means of the RGB processing. The estimating unit (35) estimates human brain activity on the basis of multiple components obtained by decomposing the blood circulation level data by means of singular value decomposition principal component analysis or independent component analysis.
