This sensor with a fine needle having a channel formed therein includes a fine needle portion of resin provided with a channel for sucking body fluid, a liquid sump portion, connected with the channel, pooling the body fluid, a sensor portion for detecting a specific component contained in the body fluid pooled in the liquid sump portion, a cover portion, in which the sensor portion is arranged, arranged to cover the liquid sump portion and an air hole connected with the channel formed in the fine needle portion through the liquid sump portion.
