A brushless motor control apparatus calculates the number of rotations of an engine based on a cycle of zero-cross points of the phase voltage induced to a sub-coil of a three-phase brushless motor. A compound having a calcium-sensing receptor antagonistic action, a pharmaceutical composition comprising the compound, particularly a calcium receptor antagonist and a therapeutic drug for osteoporosis are provided. A door is slidably mounted in the track so that a normally closed position blocks the fluid passageway.